BDBM86260 Naloxone(-) NALOXONE CAS_465-65-6 NSC_10064
US11484525, Compound Naloxone BDBM579486
(naloxone) 4-allyl-10,17-dihydroxy-(1S,5R,13R,17S)-12-oxa-4-azapentacyclo[9.6.1.01,13.05,17.07,18]octadeca-7(18),8,10-trien-14-one 4-allyl-10,17-dihydroxy-12-oxa-4-azapentacyclo[9.6.1.01,13.05,17.07,18]octadeca-7(18),8,10-trien-14-one NARCAN Analog of 14-(Arylhydroxyamino)codeinone NALOXONE SUBOXONE (naloxone)4-allyl-10,17-dihydroxy-12-oxa-4-azapentacyclo[9.6.1.01,13.05,17.07,18]octadeca-7(18),8,10-trien-14-one BDBM50000788 (morphine)4-methyl-(1S,5R,13R,14S,17R)-12-oxa-4-azapentacyclo[9.6.1.01,13.05,17.07,18]octadeca-7(18),8,10,15-tetraene-10,14-diol [17-(2,3-3H-2-propenyl)]-4, 5a -epoxy-3,14-dihydroxymorphinan-6-one (naloxone)4-allyl-10,17-dihydroxy-(1S,5R,13R,17S)-12-oxa-4-azapentacyclo[9.6.1.01,13.05,17.07,18]octadeca-7(18),8,10-trien-14-one 4-allyl-10,17-dihydroxy-(1S,5R,13R,17S)-12-oxa-4-azapentacyclo[9.6.1.01,13.05,17.07,18]octadeca-7(18),8,10-trien-14-one( Naloxone) 4-allyl-10,17-dihydroxy-(1S,5R,13R,17S)-12-oxa-4-azapentacyclo[9.6.1.01,13.05,17.07,18]octadeca-7(18),8,10-trien-14-one 4-allyl-10,17-dihydroxy-(1S,5R,13R,17S)-12-oxa-4-azapentacyclo[9.6.1.01,13.05,17.07,18]octadeca-7(18),8,10-trien-14-one(Naxolone) 4-allyl-10,17-dihydroxy-12-oxa-4-azapentacyclo[9.6.1.01,13.05,17.07,18]octadeca-7(18),8,10-trien-14-one(naloxone)C2H2O4 4-allyl-10,17-dihydroxy-(1S,5R,13R,17S)-12-oxa-4-azapentacyclo[9.6.1.01,13.05,17.07,18]octadeca-7(18),8,10-trien-14-one (naloxone)
NALOXONE HYDROCHLORIDE MLS000069540 SMR000058766 (4R,4aS,7aR,12bS)-4a,9-dihydroxy-3-prop-2-enyl-2,4,5,6,7a,13-hexahydro-1H-4,12-methanobenzofuro[3,2-e]isoquinoline-7-one;hydrochloride (4R,4aS,7aR,12bS)-3-allyl-4a,9-dihydroxy-2,4,5,6,7a,13-hexahydro-1H-4,12-methanobenzofuro[3,2-e]isoquinoline-7-one;hydrochloride cid_5464092 (4R,4aS,7aR,12bS)-4a,9-bis(oxidanyl)-3-prop-2-enyl-2,4,5,6,7a,13-hexahydro-1H-4,12-methanobenzofuro[3,2-e]isoquinoline-7-one;hydrochloride BDBM54795
(4R,4aS,7aR,12bS)-3-allyl-4a,9-dihydroxy-3-methyl-2,4,5,6,7a,13-hexahydro-1H-4,12-methanobenzofuro[3,2-e]isoquinoline-3-ium-7-one;iodide Naloxone methiodide (4R,4aS,7aR,12bS)-4a,9-dihydroxy-3-methyl-3-prop-2-enyl-2,4,5,6,7a,13-hexahydro-1H-4,12-methanobenzofuro[3,2-e]isoquinoline-3-ium-7-one;iodide MLS001334009 SMR000875254 cid_16219719 (4R,4aS,7aR,12bS)-3-methyl-4a,9-bis(oxidanyl)-3-prop-2-enyl-2,4,5,6,7a,13-hexahydro-1H-4,12-methanobenzofuro[3,2-e]isoquinoline-3-ium-7-one;iodide BDBM83098
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- Lin, SY; Kuo, YH; Tien, YW; Ke, YY; Chang, WT; Chang, HF; Ou, LC; Law, PY; Xi, JH; Tao, PL; Loh, HH; Chao, YS; Shih, C; Chen, CT; Yeh, SH; Ueng, SH The in vivo antinociceptive and ?-opioid receptor activating effects of the combination of N-phenyl-2',4'-dimethyl-4,5'-bi-1,3-thiazol-2-amines and naloxone. Eur J Med Chem 167: 312-323 (2019)
- ChEBML_148689 Inhibition of [3H]-naloxone binding to mu receptor in rat brain homogenate
- ChEMBL_1344097 (CHEMBL3254254) Displacement of [3H] naloxone from opioid receptor (unknown origin)
- ChEMBL_138861 (CHEMBL747707) Displacement of [3H]naloxone from human mu opioid receptor
- ChEMBL_143172 (CHEMBL748048) Tested for displacement of radioligand [3H]-Naloxone from opiate receptor
- ChEMBL_145416 (CHEMBL858426) Inhibition of naloxone binding to human Opioid receptor kappa 1
- ChEMBL_145631 (CHEMBL753544) Displacement of [3H]-naloxone from Opioid receptor delta 1
- ChEMBL_146288 (CHEMBL881960) Inhibition of [3H]naloxone binding to opioid receptor in presence of NaCl
- ChEMBL_147481 (CHEMBL755153) Inhibition of Opioid receptors with [3H]naloxone binding in the absence of NaCl
- ChEMBL_147639 (CHEMBL757323) Inhibition of [3H]naloxone binding to opioid receptor in presence of NaCl
- ChEMBL_147644 (CHEMBL757328) Displacement [3H]naloxone from rat-brain Opioid receptors
- ChEMBL_302913 (CHEMBL830373) Inhibition of [3H]naloxone binding to rat Opioid receptor mu
- ChEBML_222073 The binding affinity was measured on mu-opiate receptor using [3H]- naloxone as radioligand.
- ChEMBL_1341211 (CHEMBL3257278) Displacement of [3H]-(-)-naloxone from opiate receptor in rat brain membrane
- ChEMBL_148689 (CHEMBL751063) Inhibition of [3H]-naloxone binding to mu receptor in rat brain homogenate
- ChEMBL_223414 (CHEMBL844026) Inhibition of [3H]-Naloxone binding to rat brain membrane without NaCl
- ChEMBL_2272390 Displacement of [ 3H]-naloxone from rat brain membrane mu opioid receptor
- ChEMBL_60004 (CHEMBL673316) Concentration inhibiting the specific binding of [3H]naloxone by 50% in the absence of NaCl
- ChEMBL_60005 (CHEMBL673317) Concentration inhibiting the specific binding of [3H]naloxone by 50% in the presence of NaCl
- ChEBML_149455 Binding affinity for Opioid receptor mu 1 was determined by using [3H]naloxone as radioligand
- ChEMBL_143183 (CHEMBL749846) Inhibitory activity against opiate receptor in rat using [3H]naloxone as radioligand
- ChEMBL_222073 (CHEMBL843464) The binding affinity was measured on mu-opiate receptor using [3H]- naloxone as radioligand.
- ChEMBL_223413 (CHEMBL844025) Inhibition of [3H]naloxone binding to rat brain membrane with 100 mM NaCl.
- ChEMBL_303361 (CHEMBL838696) Inhibition of [3H]naloxone binding to rat brain homogenate Opioid receptor mu
- ChEMBL_303398 (CHEMBL840061) Inhibition of [3H]naloxone binding to rat brain homogenate Opioid receptor delta
- ChEMBL_378873 (CHEMBL863601) Displacement of [3H]naloxone from mu opioid receptor expressed in BHK cells
- ChEMBL_379381 (CHEMBL864838) Displacement of [3H]naloxone from mu opioid receptor expressed in BHK cells
- ChEMBL_462211 (CHEMBL945980) Displacement of [3H]naloxone from mu opioid receptor in rat brain membranes
- ChEMBL_477635 (CHEMBL928097) Displacement of [3H]naloxone from mu opioid receptor in rat brain membrane
- ChEMBL_591210 (CHEMBL1058516) Inhibition of [3H]naloxone binding to mu opioid receptor in rat brain membrane
- ChEBML_145293 Displacement of [3H]naloxone from Opioid receptor mu 1 in guinea pig brain membrane
- ChEBML_146572 Compound was tested for the binding affinity against opioid receptor mu by using [3H]naloxone as radioligand
- ChEMBL_1342217 (CHEMBL3256397) Displacement of [3H]naloxone from opioid receptor (unknown origin) by liquid scintillation counting
- ChEMBL_1360592 (CHEMBL3282287) Displacement of [3H]naloxone from opiate receptor (unknown origin) after 10 mins
- ChEMBL_145375 (CHEMBL753143) The compound was tested for the ability to displace opioid receptor kappa specific radioligand [3H]naloxone
- ChEMBL_147316 (CHEMBL755709) Inhibition of [3H]naloxone binding to Opioid receptor mu 1 in rat brain homogenate
- ChEMBL_1474606 (CHEMBL3423922) Displacement of [3H]naloxone from MOR (unknown origin) expressed in human 293T cells
- ChEMBL_147648 (CHEMBL757860) Inhibition of [3H]- naloxone binding to Opioid receptors in rat brain membrane in the absence of Na
- ChEMBL_148372 (CHEMBL757367) Inhibition of [3H]naloxone binding to Opioid receptor mu 1 in rat brain homogenate
- ChEMBL_148688 (CHEMBL751062) Inhibition of binding of [3H]naloxone to Opioid receptor mu 1 in the rat brain homogenate
- ChEMBL_149138 (CHEMBL759229) Inhibition of binding of [3H]naloxone to Opioid receptor mu 1 in the rat brain homogenate
- ChEMBL_149315 (CHEMBL757310) Binding affinity against Opioid receptor mu 1 using [3H]naloxone as radioligand.
- ChEMBL_149454 (CHEMBL758205) Binding affinity against Opioid receptor mu 1 using [3H]naloxone as radioligand.
- ChEMBL_329245 (CHEMBL864595) Displacement of [3H]naloxone from human mu opioid receptor expressed in BHK cells
- ChEMBL_378751 (CHEMBL871496) Displacement of [3H]naloxone from human mu opioid receptor expressed in BHK cells
- ChEMBL_386169 (CHEMBL871474) Activity against LFES-evoked contraction of Wistar rat vas deferens in presence of naloxone
- ChEMBL_471597 (CHEMBL940228) Displacement of [3H]naloxone from human mu opioid receptor expressed in CHOK1 cells
- ChEMBL_495338 (CHEMBL1006330) Displacement of [3H]naloxone from monocloned mu opioid receptor expressed in CHO cells
- ChEMBL_631253 (CHEMBL1114660) Displacement of [3H]naloxone from mu opioid receptor expressed in CHO cell membrane
- ChEMBL_631254 (CHEMBL1114661) Displacement of [3H]naloxone from kappa opioid receptor expressed in HEK293 cell membrane
- ChEMBL_851387 (CHEMBL2156217) Displacement of [3H]naloxone from MOR in rat brain homogenates by liquid scintillation counting
- ChEBML_146301 In vitro affinity to displace [3H]naloxone from opioid receptor in freshly prepared rat brain homogenates
- ChEBML_146550 The ability to displace [3H]-naloxone from the Opioid receptor mu isolated from rat brain membrane.
- ChEBML_147659 In vitro affinity to displace [3H]naloxone from opiate receptor in freshly prepared rat brain homogenates
- ChEBML_148678 Compound was evaluated for the inhibition of binding of [3H]naloxone toOpioid receptor mu 1 of rat brain membranes
- ChEMBL_1344098 (CHEMBL3254255) Displacement of [3H] naloxone from opioid receptor (unknown origin) in presence of 100 mM NaCl
- ChEMBL_143171 (CHEMBL744348) Concentration required to inhibit the specific binding of tritiated ligand [3H]naloxone to opiate receptor by 50%
- ChEMBL_143175 (CHEMBL749838) Concentration required to inhibit the specific binding of tritiated ligand [3H]-naloxone to opiate receptor by 50%
- ChEMBL_147509 (CHEMBL754405) Compound was tested for its ability to displace [3H]- naloxone] from Opioid receptors in absence of NaCl
- ChEMBL_147511 (CHEMBL754407) Compound was tested for its ability to displace [3H]naloxone from Opioid receptors in absence of NaCl
- ChEMBL_1925121 (CHEMBL4428193) Displacement of [3H]-naloxone from human mu opioid receptor expressed in HEK293 cell membranes
- ChEMBL_967566 (CHEMBL2399076) Displacement of [3H]naloxone from mu opioid receptor (unknown origin) after 1.5 hrs
- ChEBML_148701 The ability to displace [3H]naloxone from the Opioid receptor mu 1 isolated from rat brain membrane.
- ChEBML_148837 Ability to displace [3H]naloxone from the Opioid receptor mu 1 isolated from the rat brain membranes.
- ChEMBL_1360594 (CHEMBL3282289) Displacement of [3H]naloxone from opiate receptor (unknown origin) after 10 mins in presence of NaCl
- ChEMBL_1367238 Displacement of [3H]-naloxone from human mu-opioid receptor transfected in CHO-K1 cell by scintillation counting
- ChEMBL_146301 (CHEMBL758849) In vitro affinity to displace [3H]naloxone from opioid receptor in freshly prepared rat brain homogenates
- ChEMBL_146550 (CHEMBL754969) The ability to displace [3H]-naloxone from the Opioid receptor mu isolated from rat brain membrane.
- ChEMBL_146552 (CHEMBL754970) The ability to displace [3H]naloxone from the opioid receptor mu isolated from rat brain membrane.
- ChEMBL_147638 (CHEMBL757322) Evaluated for its concentration required for displacement of [3H]-Naloxone from opioid receptors in rat brain tissues
- ChEMBL_147649 (CHEMBL758068) Compound was evaluated for the inhibition of [3H]- naloxone binding to Opioid receptors in rat brain membrane in the presence of Na
- ChEMBL_147659 (CHEMBL756574) In vitro affinity to displace [3H]naloxone from opiate receptor in freshly prepared rat brain homogenates
- ChEMBL_148678 (CHEMBL751052) Compound was evaluated for the inhibition of binding of [3H]naloxone toOpioid receptor mu 1 of rat brain membranes
- ChEMBL_148994 (CHEMBL757978) Binding affinity towards Opioid receptor mu 1 using [3H]naloxone as radioligand in rat brain
- ChEMBL_1721390 (CHEMBL4136390) Displacement of [3H]naloxone from Mu-type opioid receptor in Sprague-Dawley rat brain membranes
- ChEMBL_767030 (CHEMBL1828461) Displacement of [3H]naloxone from mu opioid receptor expressed in CHO cells after 1 hr
- ChEMBL_878883 (CHEMBL2184596) Displacement of [3H]Naloxone from mu opioid receptor expressed in CHO cells after 1 hr
- ChEBML_146255 Binding affinity against opioid receptor mu from guinea pig brain membranes using [3H]naloxone as radioligand
- ChEMBL_1329941 (CHEMBL3227799) Displacement of [3H]-naloxone from human mu opioid receptor expressed in CHO cells after 1 hr
- ChEMBL_143174 (CHEMBL748050) Tested for displacement of radioligand [3H]-Naloxone from opiate receptor; value ranges from 7-10 uM
- ChEMBL_1453325 (CHEMBL3366609) Displacement of [3H]naloxone from human MOP receptor expressed in CHO-K1 cells by scintillation proximity assay
- ChEMBL_1460275 (CHEMBL3370191) Displacement of [3H]-naloxone from rat mu opioid receptor expressed in HEK cells after 60 mins
- ChEMBL_146553 (CHEMBL754971) The ability to displace [3H]naloxone from the opioid receptor mu isolated from rat brain membrane; >= no displacement
- ChEMBL_147482 (CHEMBL755154) Inhibition of Opioid receptors binding by inhibiting specific [3H]naloxone binding by 50% in the presence of 100 mM NaCl
- ChEMBL_147510 (CHEMBL754406) Compound was tested for its ability to displace [3H]- naloxone] from Opioid receptors in presence of NaCl (100 mM)
- ChEMBL_147512 (CHEMBL754408) Compound was tested for its ability to displace [3H]naloxone from Opioid receptors in presence of NaCl (100 mM)
- ChEMBL_147513 (CHEMBL754409) Concentration that produces 50% inhibition of stereospecific [3H]naloxone binding to opioid receptors in rat brain in absence of sodium.
- ChEMBL_147635 (CHEMBL753563) Concentration that produces 50% inhibition of stereospecific [3H]naloxone binding to opioid receptors in rat brain in presence of sodium.
- ChEMBL_147646 (CHEMBL757858) Compound was evaluated for the inhibition of [3H]- naloxone Opioid receptors binding using rat brain membrane in the absence of Na
- ChEMBL_147650 (CHEMBL758069) Compound was evaluated for the inhibition of [3H]- naloxone opiate receptor binding using rat brain membrane in the absence of Na
- ChEMBL_148701 (CHEMBL751073) The ability to displace [3H]naloxone from the Opioid receptor mu 1 isolated from rat brain membrane.
- ChEMBL_148837 (CHEMBL753955) Ability to displace [3H]naloxone from the Opioid receptor mu 1 isolated from the rat brain membranes.
- ChEMBL_1643865 (CHEMBL3992794) Displacement of [3H]naloxone from recombinant human MOR expressed in HEK cell membranes incubated for 60 mins
- ChEMBL_1832897 (CHEMBL4332905) Displacement of [3H]-naloxone from mouse MOR expressed in CHO cell membranes by competitive radioligand binding assay
- ChEMBL_1833059 (CHEMBL4333067) Inhibition of UGT2B7 in human liver microsomes assessed as reduction in naloxone 3-glucuronidation by tandem mass spectrometry analysis
- ChEMBL_980542 (CHEMBL2422701) Displacement of [3H]-naloxone from mouse mu opioid receptor expressed in CHO cells after 1.5 hrs
- ChEMBL_138749 (CHEMBL747922) In vivo binding affinity against mu opioid receptor was measured by using labeled ligand [3H]naloxone (0.5 nM)
- ChEMBL_1447930 (CHEMBL3379233) Displacement of [3H]-naloxone from human mu opioid receptor expressed in CHO-K1 cells by scintillation counting analysis
- ChEMBL_147642 (CHEMBL757326) Tested for In vitro binding constant for Opioid receptors by measuring the inhibition of stereospecific binding of [3H]naloxone in rat brain homogenates
- ChEMBL_149149 (CHEMBL759240) The ability to displace [3H]naloxone from the Opioid receptor mu 1 isolated from rat brain membrane; >= no displacement
- ChEMBL_2303204 Displacement of [ 3H]-naloxone from rat brain membrane mu opioid receptor assessed as inhibition constant by radioligand binding assay
- ChEBML_145291 Binding affinity against Opioid receptor mu 1 of guinea pig brain membranes using 0.5 nM of [3H]naloxone as radioligand
- ChEMBL_1341239 (CHEMBL3257740) Displacement of [3H]naloxone from Sprague-Dawley rat cerebellum opioid receptor assessed as relative receptor affinity by scintillation counting
- ChEMBL_1354145 (CHEMBL3280909) Displacement of [3H]-naloxone from rat opioid receptor after 30 mins by liquid scintillation counting analysis in absence of NaCl
- ChEMBL_1354146 (CHEMBL3280910) Displacement of [3H]-naloxone from rat opioid receptor after 30 mins by liquid scintillation counting analysis in presence of NaCl
- ChEMBL_1452451 (CHEMBL3362475) Displacement of [3H]Naloxone from human mu opioid receptor receptor expressed in CHO-K1 cells after 90 mins
- ChEMBL_146283 (CHEMBL756528) Concentration for 50% inhibition of [3H]naloxone (1 M) binding to opioid receptor in rat brain membrane was determined in the absence of NaCl
- ChEMBL_146284 (CHEMBL756529) Concentration for 50% inhibition of [3H]naloxone (1 M) binding to opioid receptor in rat brain membrane was determined in the presence of NaCl
- ChEMBL_147647 (CHEMBL757859) Compound was evaluated for the inhibition of [3H]- naloxone Opioid receptors binding using rat brain membrane in the presence of 100 mM Na
- ChEMBL_149148 (CHEMBL759239) The ability to displace [3H]naloxone from the Opioid receptor mu 1 isolated from rat brain membrane; >= absolutely no % change
- ChEMBL_1859880 (CHEMBL4360736) Agonist activity at MOR in Wistar rat brain membranes in presence of naloxone after 60 mins by [35S]-GTPgammaS binding assay
- ChEMBL_2158151 (CHEMBL5042901) Displacement of [3H]-naloxone from mouse MOR expressed in CHO cells incubated for 1.5 hrs by competitive radioligand binding assay
- ChEMBL_971894 (CHEMBL2405344) Activity at Wistar rat NOP receptor assessed as inhibition of low-frequency electrically-stimulated vas deferens contraction in presence of naloxone
- ChEMBL_971762 (CHEMBL2404598) Activity at Wistar rat mu opioid receptor assessed as inhibition of low-frequency electrically-stimulated vas deferens contraction in presence of naloxone
- ChEMBL_1581405 (CHEMBL3812012) Displacement of [3H]naloxone from human MOR expressed in CHO-K1 cell membranes after 60 mins by microbeta scintillation counting method
- ChEMBL_1825157 (CHEMBL4324921) Displacement of [3H]-Naloxone from mouse mu opioid receptor expressed in CHO cells incubated for 1.5 hrs by competitive radioligand binding assay
- ChEMBL_971896 (CHEMBL2405346) Activity at Wistar rat NOP/mu opioid receptor assessed as inhibition of low-frequency electrically-stimulated vas deferens contraction in presence of naloxone
- ChEMBL_1929931 (CHEMBL4433107) Displacement of [3H]-naloxone human mu-opioid receptor expressed in CHO-K1 cell membranes measured after 90 mins by beta-counter method
- ChEMBL_2109217 (CHEMBL4817892) Displacement of [3H]-naloxone from mu opioid receptor (unknown origin) expressed in CHO cell membranes incubated for 1 hr by competitive radioligand binding assay
- ChEMBL_2164694 (CHEMBL5049555) Displacement of [3H]-naloxone from mouse mu opioid receptor expressed in CHO cell membranes assessed as inhibition constant incubated for 1.5 hrs by competitive binding assay
- ChEMBL_1925133 (CHEMBL4428205) Displacement of [N-allyl-2,3-3H]naloxone from recombinant human mu opioid receptor expressed in CHOK1 cell membranes after 90 mins by scintillation counting method
- ChEBML_145705 Inhibition against binding of radioligand [N-allyl-2-3-3H]-naloxone to membrane of baby hamster kidney cells infected with forest virus encoding the cDNAs for rat Opioid receptor kappa 1
- ChEBML_149009 Inhibition against binding of radioligand [N-allyl-2-3-3H]-naloxone to membrane of baby hamster kidney cells infected with forest virus encoding the cDNAs for rat Opioid receptor mu 1
- ChEMBL_145705 (CHEMBL753913) Inhibition against binding of radioligand [N-allyl-2-3-3H]-naloxone to membrane of baby hamster kidney cells infected with forest virus encoding the cDNAs for rat Opioid receptor kappa 1
- ChEMBL_148832 (CHEMBL753950) Inhibition against binding of radioligand [N-allyl-2-3-3H]-naloxone to membrane of baby hamster kidney cells infected with forest virus encoding the cDNAs for rat Opioid receptor mu 1
- ChEMBL_1889207 (CHEMBL4390961) Agonist activity at human mu opioid receptor expressed in CHOK1 cells coexpressing Galpha15 assessed as increase in intracellular calcium flux in presence of mu opioid receptor antagonist naloxone and incubated for 1 hr measured for 90 secs at 1.5 sec interval by FLIPR assay
- Receptor Binding Assay Affinities of various compounds were measured in vitro using competitive radioligand binding assays. Serial dilutions of test compounds were incubated with membranes prepared from CHO-K1 cells expressing the mu opioid receptor (MOR; for opioid receptor binding) or rat forebrain membranes (for NMDA receptor binding). 2 nM [3H] Naloxone (MOR) or 0.2 nM [3H] MK801 (NMDA) were used as the specific, competitive radioligands. 10 uM Naloxone (MOR), or 10 uM MK801 (NMDA) was used to determine non-specific binding. Bound radioactivity was measured using a scintillation counter & IC50 values for test compounds were determined by non-linear regression analysis using a one-site competition model (Graph Pad Prizm). Due to each test compound being solubilized in a buffered system for the assay, the results presented herein reflect the free base activity.
- Human Mu-Opioid Peptide (hMOP) Receptor Binding Assay The hMOP receptor binding assay was performed as homogeneous SPA-assay (scintillation proximity assay) using the assay buffer 50 mM TRIS-HCl (pH 7.4) supplemented with 0.052 mg/ml bovine serum albumin (Sigma-Aldrich Co. St. Louis. Mo.). The final assay volume (250 l/well) included 1 nM of [N-allyl-2.3-3H]naloxone as ligand (PerkinElmer Life Sciences. Inc. Boston. Mass. USA). and either test compound in dilution series or 25 μM unlabelled naloxone for determination of unspecific binding. The test compound was diluted with 25% DMSO in H2O to yield a final 0.5% DMSO concentration. which also served as a respective vehicle control. The assay was started by adding wheat germ agglutinin coated SPA beads (GE Healthcare UK Ltd. Buckinghamshire. UK) which had been preloaded with hMOP receptor membranes (PerkinElmer Life Sciences. Inc. Boston. Mass. USA). After incubation for 90 minutes at RT and centrifugation for 20 minutes at 500 rpm the signal rate was measured by means of a 1450 Microbeta Trilux β-counter (PerkinElmer Life Sciences/Wallac. Turku. Finland). Half-maximal inhibitory concentration (IC50) values reflecting 50% displacement of [3H]naloxone-specific receptor binding were calculated by nonlinear regression analysis and Ki values were calculated by using the Cheng-Prusoff equation. (Cheng and Prusoff. 1973).
- Human Mu-Opioid Peptide (hMOP) Receptor Binding Assay The hMOP receptor binding assay was performed as homogeneous SPA-assay (scintillation proximity assay) using the assay buffer 50 mM TRIS-HCl (pH 7.4) supplemented with 0.052 mg/ml bovine serum albumin (Sigma-Aldrich Co., St. Louis, Mo.). The final assay volume (250 μl/well) included 1 nM of [N-allyl-2,3-3H]naloxone as ligand (PerkinElmer Life Sciences, Inc. Boston, Mass., USA), and either test compound in dilution series or 25 μM unlabelled naloxone for determination of unspecific binding. The test compound was diluted with 25% DMSO in H2O to yield a final 0.5% DMSO concentration, which also served as a respective vehicle control. The assay was started by adding wheat germ agglutinin coated SPA beads (GE Healthcare UK Ltd., Buckinghamshire, UK) which had been preloaded with hMOP receptor membranes (PerkinElmer Life Sciences, Inc. Boston, Mass., USA). After incubation for 90 minutes at RT and centrifugation for 20 minutes at 500 rpm the signal rate was measured by means of a 1450 Microbeta Trilux -counter (PerkinElmer Life Sciences/Wallac, Turku, Finland). Half-maximal inhibitory concentration (IC50) values reflecting 50% displacement of [3H]naloxone-specific receptor binding were calculated by nonlinear regression analysis and Ki values were calculated by using the Cheng-Prusoff equation, (Cheng and Prusoff, 1973).
- Receptor Binding Assay MOP: The hMOP receptor binding assay was performed as homogeneous SPA-assay (scintillation proximity assay) using the assay buffer 50 mM TRIS-HCl (pH 7.4) supplemented with 0.052 mg/ml bovine serum albumin (Sigma-Aldrich Co. St. Louis. Mo.). The final assay volume (250 μl/well) included 1 nM of [N-allyl-2.3-3H]naloxone as ligand (PerkinElmer Life Sciences. Inc. Boston. Mass. USA). and either test compound in dilution series or 25 μM unlabelled naloxone for determination of unspecific binding. The test compound was diluted with 25% DMSO in H2O to yield a final 0.5% DMSO concentration. which also served as a respective vehicle control. The assay was started by adding wheat germ agglutinin coated SPA beads (GE Healthcare UK Ltd. Buckinghamshire. UK) which had been preloaded with hMOP receptor membranes (PerkinElmer Life Sciences. Inc. Boston. Mass. USA). After incubation for 90 minutes at RT and centrifugation for 20 minutes at 500 rpm the signal rate was measured by means of a 1450 Microbeta Trilux -counter (PerkinElmer Life Sciences/Wallac. Turku. Finland). Half-maximal inhibitory concentration (IC50) values reflecting 50% displacement of [3H]naloxone-specific receptor binding were calculated by nonlinear regression analysis and Ki values were calculated by using the Cheng-Prusoff equation.
- Receptor Binding Assay Mu-Opioid Peptide (hMOP): The hMOP receptor binding assay was performed as homogeneous SPA-assay (scintillation proximity assay) using the assay buffer 50 mM TRIS-HCl (pH 7.4) supplemented with 0.052 mg/ml bovine serum albumin (Sigma-Aldrich Co. St. Louis. Mo.). The final assay volume (250 μl/well) included 1 nM of [N-allyl-2.3-3H]naloxone as ligand (PerkinElmer Life Sciences. Inc. Boston. Mass. USA). and either test compound in dilution series or 25 μM unlabelled naloxone for determination of unspecific binding. The test compound was diluted with 25% DMSO in H2O to yield a final 0.5% DMSO concentration. which also served as a respective vehicle control. The assay was started by adding wheat germ agglutinin coated SPA beads (GE Healthcare UK Ltd. Buckinghamshire. UK) which had been preloaded with hMOP receptor membranes (PerkinElmer Life Sciences. Inc. Boston. Mass. USA). After incubation for 90 minutes at RT and centrifugation for 20 minutes at 500 rpm the signal rate was measured by means of a 1450 Microbeta Trilux β-counter (PerkinElmer Life Sciences/Wallac. Turku. Finland). Half-maximal inhibitory concentration (IC50) values reflecting 50% displacement of [3H]naloxone-specific receptor binding were calculated by nonlinear regression analysis and Ki values were calculated by using the Cheng-Prusoff equation.
- Receptor Binding Assay The hMOP receptor binding assay was performed as homogeneous SPA-assay (scintillation proximity assay) using the assay buffer 50 mM TRIS-HCl (pH 7.4) supplemented with 0.052 mg/ml bovine serum albumin (Sigma-Aldrich Co. St. Louis. Mo.). The final assay volume (250 ul/well) included 1 nM of [N-allyl-2.3-3H]naloxone as ligand (PerkinElmer Life Sciences. Inc. Boston. Mass. USA). and either test compound in dilution series or 25 uM unlabelled naloxone for determination of unspecific binding. The test compound was diluted with 25% DMSO in H2O to yield a final 0.5% DMSO concentration. which also served as a respective vehicle control. The assay was started by adding wheat germ agglutinin coated SPA beads (GE Healthcare UK Ltd. Buckinghamshire. UK) which had been preloaded with hMOP receptor membranes (PerkinElmer Life Sciences. Inc. Boston. Mass. USA). After incubation for 90 minutes at RT and centrifugation for 20 minutes at 500 rpm the signal rate was measured by means of a 1450 Microbeta Trilux ??-counter (PerkinElmer Life Sciences/Wallac. Turku. Finland). Half-maximal inhibitory concentration (IC50) values reflecting 50% displacement of [3H]naloxone-specific receptor binding were calculated by nonlinear regression analysis and Ki values were calculated by using the Cheng-Prusoff equation. (Cheng and Prusoff. 1973).
- Binding Assay The receptor affinity for the human mu-opiate receptor was determined in a homogeneous batch in microtitre plates. For this, dilution series of the particular spirocyclic cyclohexane derivative to be tested were incubated in a total volume of 250 ul for 90 minutes at room temperature with a receptor membrane preparation (15-40 ug protein per 250 ul incubation batch) of CHO-K1 cells, which express the human mu-opiate receptor (RB-HOM receptor membrane preparation of NEN, Zaventem, Belgium), in the presence of 1 nmol/l of the radioactive ligand [3H]-naloxone (NET719, NEN, Zaventem, Belgium) and of 1 mg WGA-SPA beads (wheat germ agglutinin SPA beads from Amersham/Pharmacia, Freiburg, Germany). 50 mmoles/l Tris-HCl supplemented with 0.05 wt. % sodium azide and with 0.06 wt. % bovine serum albumin was used as the incubation buffer. 25 umoles/l naloxone was additionally added for determination of the non-specific binding.
- Binding Assay The affinity to the human μ-opiate receptor was determined in a homogeneous preparation in microtiter plates. For this, dilution series of the respective compound to be tested were incubated for 90 minutes at room temperature with a receptor membrane preparation (15-40 mg of protein per 250 μl of incubation batch) of CHO-K 1 cells, which express the human μ-opiate receptor (RB-HOM receptor membrane preparation of NEN, Zaventem, Belgium), in the presence of 1 nmol/l of the radioactive ligand [3H'-naloxone (NET719, NEN, Zaventem, Belgium) and of 1 mg WGA-SPA beads (wheat germ agglutinin SPA beads from Amersham/Pharmacia, Freiburg, Germany) in a total volume of 250 μl. 50 mmol/l of tris-HCl supplemented by 0.05% by wt. of sodium azide and 0.06% by wt. of bovine serum albumin was used as incubation buffer. 25 μmol/l of naloxone were additionally added to determine the non-specific bond. After the ninety-minute incubation time had ended, the microtiter plates were centrifuged for 20 minutes at 1000 g and the radioactivity measured in a β-counter (Microbeta-Trilux, PerkinElmer Wallac, Freiburg, Germany).
- Receptor Binding Assay The hMOP receptor binding assay was performed as homogeneous SPA-assay (scintillation proximity assay) using the assay buffer 50 mM TRIS-HCl (pH 7.4) supplemented with 0.052 mg/ml bovine serum albumin (Sigma-Aldrich Co. St. Louis, Mo.). The final assay volume (250 μl/well) included 1 nM of [N-allyl-2.3-3H]naloxone as ligand (PerkinElmer Life Sciences. Inc. Boston, Mass. USA) and either test compound in dilution series or 25 μM unlabelled naloxone for determination of unspecific binding. The test compound was diluted with 25% DMSO in H2O to yield a final 0.5% DMSO concentration which also served as a respective vehicle control. The assay was started by adding wheat germ agglutinin coated SPA beads (GE Healthcare UK Ltd. Buckinghamshire. UK) which had been preloaded with hMOP receptor membranes (PerkinElmer Life Sciences. Inc. Boston, Mass. USA). After incubation for 90 minutes at RT and centrifugation for 20 minutes at 500 rpm the signal rate was measured by means of a 1450 Microbeta Trilux -counter.
- μ-Opioid Receptor Binding Assays μ-Opioid Receptor Binding Assay Procedures: Radioligand dose-displacement binding assays for μ-opioid receptors used 0.2 nM[3H]-diprenorphine (NEN, Boston, Mass.), with 5-20mg membrane protein/well in a final volume of 500 μL binding buffer (10 mM MgCl2, 1 mM EDTA, 5% DMSO, 50 mM HEPES, pH 7.4). Reactions were carried out in the absence or presence of increasing concentrations of unlabeled naloxone. All reactions were conducted in 96-deep well polypropylene plates for 1-2 h at about 25° C.
- δ-Opioid Receptor Binding Assays δ-Receptor Binding Assay Procedures: Radioligand dose-displacement assays used 0.2 nM [3H]-Naltrindole (NEN; 33.0 Ci/mmole) with 10-20 μg membrane protein (recombinant delta opioid receptor expressend in CHO-K1 cells; Perkin Elmer) in a final volume of 5004 binding buffer (5 mM MgCl2, 5% DMSO, 50 mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 25μm M unlabeled naloxone. All reactions were performed in 96-deep well polypropylene plates for 1 h at a temperature of about 25° C.
- In Vitro Radioligand Binding Assay The competition binding assay was conducted using monoclonal mouse MOR expressed in Chinese hamster ovary (CHO) cell lines. In this assay, 30 μg of membrane protein was incubated with the radioligand [3H] naloxone in the presence of different concentrations of tested compounds in TME buffer (50 mM Tris, 3 mM MgCl2, and 0.2 mM EGTA, pH 7.4) for 1.5 h at 30° C. The bound radioligand was separated by filtration using a Brandel harvester. Specific (i.e., opioid receptor-related) binding to the MOR was determined as the difference in binding obtained in the absence and presence of 5 μM of DAMGO. The IC50 values were determined and converted to Ki values using the Cheng-Prusoff equation: Ki=IC50/[1+([L*]/KD)], where [L*] is the concentration of the radioligand and KD is the KD of the radioligand was determined.
- Ligand Binding Assay As Alt et al., 2002. Membranes (20 μg) are incubated in 50 mM Tris-HCl, pH 7.4 with [3H]diprenorphine or [3H]nociceptin in the absence or presence of varying concentrations of test compounds for 60 min in a shaking water bath at 25° C. Nonspecific binding is measured using 10 μM naloxone (MOR, DOR, KOR) or N/OFQ (NOP). Samples are filtered through GF/C glass-fiber filtermats mounted on a Brandel cell harvester and rinsed four times with 4° C. 50 mM Tris-HCl, pH 7.4 buffer. Filtermats are dried and 0.1 ml EcoLume scintillation cocktail added to each sample area to soak the filter. Each filtermat in a heat-sealed bag, is counted in a Wallac 1450 MicroBeta Liquid Scintillation and Luminescence Counter.
- Ligand Binding Assays As Alt et al., 2002. Membranes (20 ug) are incubated in 50 mM Tris-HCl, pH 7.4 with [3H]diprenorphine or [3H]nociceptin in the absence or presence of varying concentrations of test compounds for 60 min in a shaking water bath at 25° C. Nonspecific binding is measured using 10 uM naloxone (MOR, DOR, KOR) or N/OFQ (NOP). Samples are filtered through GF/C glass-fiber filtermats mounted on a Brandel cell harvester and rinsed four times with 4° C. 50 mM Tris-HCl, pH 7.4 buffer. Filtermats are dried and 0.1 ml EcoLume scintillation cocktail added to each sample area to soak the filter. Each filtermat in a heat-sealed bag, is counted in a Wallac 1450 MicroBeta Liquid Scintillation and Luminescence Counter.
- Human mu-Opioid Receptor Radioligand Assay To investigate binding properties of test compounds to human μ-opioid receptor, transfected CHO-K1 cell membranes and [3H]-DAMGO (Perkin Elmer, ES-542-C), as the radioligand, were used. The assay was carried out with 20 μg of membrane suspension, 1 nM of [3H]-DAMGO in either absence or presence of either buffer or 10 μM Naloxone for total and non-specific binding, respectively. Binding buffer contained Tris-HCl 50 mM, MgCl2 5 mM at pH 7.4. Plates were incubated at 27° C. for 60 minutes. After the incubation period, the reaction mix was then transferred to MultiScreen HTS, FC plates (Millipore), filtered and plates were washed 3 times with ice-cold 10 mM Tris-HCL (pH 7.4). Filters were dried and counted at approximately 40% efficiency in a MicroBeta scintillation counter (Perkin-Elmer) using EcoScint liquid scintillation cocktail.
- Competitive Displacement Assay Receptor Binding (in vitro Assay) The Ki (binding affinity) for mu-, delta-, and kippa-receptors was determined with a previously described method using a competitive displacement assay (Neumeyer, 2003). Membrane protein from CHO (Chinese Hamster Ovarian) cells that stably expressed one type of the cloned human opioid receptor were incubated with 12 different concentrations of the compound in the presence of 0.25 nM [3H]DAMGO, 0.2 nM [3H]naltrindole or 1 nM [3H]U69,593 in a final volume of 1 mL of 50 mM Tris-HCl, pH 7.5 at 25 C. Incubation times of 60 min were used for [3H]DAMGO and [3H]U69,593. Because of a slower association of [3H]naltrindole with the receptor, a 3 h incubation was used with this radioligand. Samples incubated with [3H]naltrindole also contained 10 mM MgCl2 and 0.5 mM phenylmethylsulfonyl fluoride. Nonspecific binding was measured by inclusion of 10 uM naloxone. The binding was terminated by filtering the samples through Schleicher & Schuell No. 32 glass.
- Radioligand Dose-Displacement Binding Assay Radioligand dose displacement assays used 0.4 nM [3H]-U69,593 (GE Healthcare, Piscataway, N.J.; 40 Ci/mmole) with 15 ug membrane protein (recombinant kippa opioid receptor expressed in HEK 293 cells; in-house prep) in a final volume of 200 ul binding buffer (5% DMSO, 50 mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 10 uM unlabeled naloxone or U69,593. All reactions were performed in 96-well polypropylene plates for 1 hour at a temperature of about 25 C. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.) presoaked in 0.5% polyethylenimine (Sigma). Harvesting was performed using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by five filtration washes with 200 ul ice-cold binding buffer. Filter plates were subsequently dried at 50 C. for 1-2 hours.
- Radioligand Dose-Displacement Binding Assay Radioligand dose-displacement binding assays for μ-opioid receptors used 0.3 nM [3H]-diprenorphine (Perkin Elmer, Shelton, Conn.), with 5 mg membrane protein/well in a final volume of 500 μl binding buffer (10 mM MgCl2, 1 mM EDTA, 5% DMSO, 50 mM HEPES, pH 7.4). Reactions were carried out in the absence or presence of increasing concentrations of unlabeled naloxone. All reactions were conducted in 96-deep well polypropylene plates for 2 hours at room temperature. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.), presoaked in 0.5% polyethylenimine using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by performing three filtration washes with 500 μl of ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 2-3 hours.
- Beta-Opioid Binding Assay Radioligand dose-displacement assays used 0.2 nM [3H]-Naltrindole (NEN; 33.0 Ci/mmole) with 10-20 ug membrane protein (recombinant delta opioid receptor expressend in CHO-K1 cells; Perkin Elmer) in a final volume of 500 uL binding buffer (5 mM MgCl2, 5% DMSO, 50 mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 25 uM unlabeled naloxone. All reactions were performed in 96-deep well polypropylene plates for 1 h at a temperature of about 25 °C. Binding reactions were determined by rapid filtration onto 96-well Unifilter GF/C filter plates (Packard) presoaked in 0.5% polyethylenimine (Sigma). Harvesting was performed using a 96-well tissue harvester (Packard) followed by five filtration washes with 500 uL ice-cold binding buffer. Filter plates were subsequently dried at 50 °C. for 1-2 hours. Fifty uL/well scintillation cocktail (MicroScint20, Packard) was added.
- Binding Assay Delta-Opioid Receptor Binding Assay Procedures: delta-opioid Receptor Binding Assay Procedures were conducted as follows. Radioligand dose-displacement assays used 0.3 nM [3H]-Naltrindole (Perkin Elmer, Shelton, Conn.; 33.0 Ci/mmole) with 5 ug membrane protein (Perkin Elmer, Shelton, Conn.) in a final volume of 500 ul binding buffer (5 mM MgCl2, 5% DMSO, 50 mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 25 uM unlabeled naloxone. All reactions were performed in 96-deep well polypropylene plates for 1 hr at a temperature of about 25 C. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.) presoaked in 0.5% polyethylenimine (Sigma). Harvesting was performed using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by five filtration washes with 500 ul ice-cold binding buffer. Filter plates were subsequently dried at 50 C. for 1-2 hours.
- Binding Assay The determination occurred in a homogeneous batch in microtiter plates. For this, dilution series of the respective substances to be tested were incubated for 90 minutes at room temperature with a receptor membrane preparation (7 μg of protein per 250 μl of incubation batch) of CHO-K 1 cells, which express the human κ-opiate receptor, in the presence of 1 nmol/l of the radioactive ligand [3H']−Cl-977 and 1 mg WGA-SPA beads (wheat germ agglutinin SPA beads from Amersham/Pharmacia, Freiburg, Germany) in a total volume of 250 μl. 50 mmol/l of tris-HCl supplemented by 0.05% by wt. of sodium azide and 0.06% by wt. of bovine serum albumin was used as incubation buffer. 100 μmol/l of naloxone were additionally added to determine the non-specific bond. After the ninety-minute incubation time had ended, the microtiter plates were centrifuged for 20 minutes at 500 rpm and the radioactivity measured in a β-counter (Microbeta-Trilux 1450, PerkinElmer Wallac, Freiburg, Germany).
- Binding Assay u-Opioid Receptor Binding Assay Procedures: Radioligand dose-displacement binding assays for u-opioid receptors used 0.3 nM [3H]-diprenorphine (Perkin Elmer, Shelton, Conn.), with 5 mg membrane protein/well in a final volume of 500 ul binding buffer (10 mM MgCl2, 1 mM EDTA, 5% DMSO, 50 mM HEPES, pH 7.4). Reactions were carried out in the absence or presence of increasing concentrations of unlabeled naloxone. All reactions were conducted in 96-deep well polypropylene plates for 2 hr at room temperature. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.), presoaked in 0.5% polyethylenimine using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by performing three filtration washes with 500 ul of ice-cold binding buffer. Filter plates were subsequently dried at 50 C. for 2-3 hours. BetaScint scintillation cocktail (Perkin Elmer, Shelton, Conn.) was added (50 ul/well).
- Radioligand Binding Assay Radioligand dose displacement assays used 0.4-0.8nM [3H]-U69,593 (NEN; 40 Ci/mmole) with 10-20 ug membrane protein (recombinant kappa opioid receptor expressed in HEK 293 cells; in-house prep) in a final volume of 200 uL binding buffer (5% DMSO, 50mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 10 uM unlabeled naloxone or U69,593. All reactions were performed in 96-well polypropylene plates for 1 h at a temperature of about 25C. Binding reactions were determined by rapid filtration onto 96-well Unifilter GF/C filter plates (Packard) presoaked in 0.5% polyethylenimine (Sigma). Harvesting was performed using a 96-well tissue harvester (Packard) followed by five filtration washes with 200uL ice-cold binding buffer. Filter plates were subsequently dried at 50C for 1-2 hours. Fifty uL/well scintillation cocktail (MicroScint20, Packard) was added and plates were counted in a Packard Top-Count for 1 min/well.
- Radioligand Binding Assay Radioligand dose-displacement assays used 0.2nM [3H]-Naltrindole (NEN; 33.0 Ci/mmole) with 10-20ug membrane protein (recombinant delta opioid receptor expressend in CHO-K1 cells; Perkin Elmer) in a final volume of 500uL binding buffer (5mM MgCl2, 5% DMSO, 50mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 25 uM unlabeled naloxone. All reactions were performed in 96-deep well polypropylene plates for 1 h at a temperature of about 25C. Binding reactions were determined by rapid filtration onto 96-well Unifilter GF/C filter plates (Packard) presoaked in 0.5% polyethylenimine (Sigma). Harvesting was performed using a 96-well tissue harvester (Packard) followed by five filtration washes with 500uL ice-cold binding buffer. Filter plates were subsequently dried at 50C for 1-2 hours. Fifty uL/well scintillation cocktail (MicroScint20, Packard) was added and plates were counted in a Packard Top-Count for 1 min/well.
- Radioligand Binding Assay Radioligand dose-displacement binding assays for u-opioid receptors used 0.2nM[3H]-diprenorphine (NEN, Boston, Mass.), with 5-20mg membrane protein/well in a final volume of 500 uL binding buffer (10mM MgCl2, 1mM EDTA, 5% DMSO, 50mM HEPES, pH 7.4). Reactions were carried out in the absence or presence of increasing concentrations of unlabeled naloxone. All reactions were conducted in 96-deep well polypropylene plates for 1-2 hr at about 25C. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Packard, Meriden, Conn.) presoaked in 0.5% polyethylemimine using a 96-well tissue harvester (Brandel, Gaithersburg, Md.) followed by performing three filtration washes with 500uL of ice-cold binding buffer. Filter plates were subsequently dried at 50C for 2-3 hours. BetaScint scintillation cocktail (Wallac, Turku, Finland) was added (50uL/well), and plates were counted using a Packard Top-Count for 1 min/well.
- Radioligand Dose-Displacement Binding Assay Delta-opioid Receptor Binding Assay Procedures were conducted as follows. Radioligand dose-displacement assays used 0.3 nM [3H]-Naltrindole (Perkin Elmer, Shelton, Conn.; 33.0 Ci/mmole) with 5 ug membrane protein (Perkin Elmer, Shelton, Conn.) in a final volume of 500 ul binding buffer (5 mM MgCl2, 5% DMSO, 50 mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 25 uM unlabeled naloxone. All reactions were performed in 96-deep well polypropylene plates for 1 hr at a temperature of about 25° C. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.) presoaked in 0.5% polyethylenimine (Sigma). Harvesting was performed using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by five filtration washes with 500 ul ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 1-2 hours.
- Radioligand Dose-Displacement Binding Assay Radioligand dose displacement assays used 0.4 nM [3H]-U69,593 (GE Healthcare, Piscataway, N.J.; 40 Ci/mmole) with 15 μg membrane protein (recombinant κ opioid receptor expressed in HEK 293 cells; in-house prep) in a final volume of 200 μl binding buffer (5% DMSO, 50 mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 10 μM unlabeled naloxone or U69,593. All reactions were performed in 96-well polypropylene plates for 1 hour at a temperature of about 25° C. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.) presoaked in 0.5% polyethylenimine (Sigma). Harvesting was performed using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by five filtration washes with 200 μl ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 1-2 hours.
- Radioligand Dose-Displacement Binding Assay Radioligand dose displacement assays used 0.4 nM [3H]-U69,593 (GE Healthcare, Piscataway, N.J.; 40 Ci/mmole) with 15 μg membrane protein (recombinant κ opioid receptor expressed in HEK 293 cells; in-house prep) in a final volume of 200 μl binding buffer (5% DMSO, 50 mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 10 μM unlabeled naloxone or U69,593. All reactions were performed in 96-well polypropylene plates for 1 hour at a temperature of about 25° C. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.) presoaked in 0.5% polyethylenimine (Sigma). Harvesting was performed using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by five filtration washes with 200 μl ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 1-2 hours.
- Radioligand Dose-Displacement Binding Assay Radioligand dose displacement assays used 0.4 nM [3H]-U69,593 (GE Healthcare, Piscataway, N.J.; 40 Ci/mmole) with 15 μg membrane protein (recombinant κ opioid receptor expressed in HEK 293 cells; in-house prep) in a final volume of 200 μl binding buffer (5% DMSO, 50 mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 10 μM unlabeled naloxone or U69,593. All reactions were performed in 96-well polypropylene plates for 1 hr at a temperature of about 25° C. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.) presoaked in 0.5% polyethylenimine (Sigma). Harvesting was performed using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by five filtration washes with 2001 ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 1-2 hours.
- mu-Opioid Receptor Binding Assay Radioligand dose-displacement binding assays for mu-opioid receptors used 0.2 nM[3H]-diprenorphine (NEN, Boston, Mass.), with 5-20 mg membrane protein/well in a final volume of 500 uL binding buffer (10 mM MgCl2, 1 mM EDTA, 5% DMSO, 50 mM HEPES, pH 7.4). Reactions were carried out in the absence or presence of increasing concentrations of unlabeled naloxone. All reactions were conducted in 96-deep well polypropylene plates for 1-2 hr at about 25 °C. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Packard, Meriden, Conn.) presoaked in 0.5% polyethylenimine using a 96-well tissue harvester (Brandel, Gaithersburg, Md.) followed by performing three filtration washes with 5004, of ice-cold binding buffer. Filter plates were subsequently dried at 50 °C. for 2-3 hours. BetaScint scintillation cocktail (Wallac, Turku, Finland) was added (50 uL/well).
- null The Ki (binding affinity) for u opioid receptors was determined using a competitive displacement assay as previously described in Neumeyer (Journal of Med. Chem. 2012, p 3878), which is incorporated herein in its entirety. Briefly, membrane protein from CHO (Chinese Hamster Ovarian) cells that stably expressed the cloned human u opioid receptor were incubated with 12 different concentrations of the compound set forth herein in the presence of 0.25 nM [3H]DAMGO (see Tiberi et al., Can. J. Physiol. Pharmacol. 1988, Vol. 66, p 1368, which is incorporated by reference herein in its entirety) in a final volume of 1 mL of 50 mM Tris-HCl, pH 7.5 at 25° C. Incubation times of 60 min were used for [3H]DAMGO (see Gulati et al., Life Sci. 1990, Vol. 47, p 159, which is incorporated by reference herein in its entirety). Nonspecific binding was measured by inclusion of 10 uM naloxone. The binding was terminated by filtering the samples through Schleicher & Schuell No. 32 glass fiber.
- κ-opioid Receptor Binding Assay Radioligand dose displacement assays used 0.4-0.8 nM [3H]-U69,593 (NEN; 40 Ci/mmole) with 10-20 μg membrane protein (recombinant kappa opioid receptor expressed in HEK 293 cells; in-house prep) in a final volume of 200 μL binding buffer (5% DMSO, 50 mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 10 μM unlabeled naloxone or U69,593. All reactions were performed in 96-well polypropylene plates for 1 h at a temperature of about 25° C. Binding reactions were determined by rapid filtration onto 96-well Unifilter GF/C filter plates (Packard) presoaked in 0.5% polyethylenimine (Sigma). Harvesting was performed using a 96-well tissue harvester (Packard) followed by five filtration washes with 2004 ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 1-2 hours. Fifty μL/well scintillation cocktail (MicroScint20, Packard) was added and plates were counted in a Packard Top-Count for 1 min/well.
- Radioligand Binding Assay Radioligand binding assays were conducted using freshly thawed membranes expressing human mu-receptors (Perkin Elmer, Shelton, Conn.). Radioligand dose-displacement binding assays for human mu-opioid receptors used 0.2 nM[3H]-diprenorphine (NEN, Boston, Mass.), with 5-20 mg membrane protein/well in a final volume of 500 uL binding buffer (10 mM MgCl2, 1 mM EDTA, 5% DMSO, 50 mM HEPES, pH 7.4). Reactions were carried out in the absence or presence of increasing concentrations of unlabeled naloxone. All reactions were conducted in 96-deep well polypropylene plates for 1-2 hrs at about 25 C. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Packard, Meriden, Conn.) presoaked in 0.5% polyethylenimine using a 96-well tissue harvester (Brandel, Gaithersburg, Md.) followed by performing three filtration washes with 500 uL of ice-cold binding buffer. Filter plates were subsequently dried at 50 C. for 2-3 hrs.
- Radioligand Binding Assay Radioligand dose displacement assays used 0.4-0.8 nM [3H]-U69,593 (NEN; 40 Ci/mmole) with 10-20 μg membrane protein (recombinant kappa opioid receptor expressed in HEK 293 cells; in-house prep) in a final volume of 200 μL binding buffer (5% DMSO, 50 mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 10 μM unlabeled naloxone or U69,593. All reactions were performed in 96-well polypropylene plates for 1 h at a temperature of about 25° C. Binding reactions were determined by rapid filtration onto 96-well Unifilter GF/C filter plates (Packard) presoaked in 0.5% polyethylenimine (Sigma-Aldrich). Harvesting was performed using a 96-well tissue harvester (Packard) followed by five filtration washes with 200 μL ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 1-2 hrs. Fifty μL/well scintillation cocktail (MicroScint20, Packard) was added and plates were counted in a Packard Top-Count for 1 min/well.
- Radioligand Binding Assay Radioligand dose-displacement assays used 0.2 nM [3H]-Naltrindole (NEN; 33.0 Ci/mmole) with 10-20 μg membrane protein (recombinant delta opioid receptor expressed in CHO-K1 cells; Perkin Elmer) in a final volume of 500 μL binding buffer (5 mM MgCl2, 5% DMSO, 50 mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 25 μM unlabeled naloxone. All reactions were performed in 96-deep well polypropylene plates for 1 h at a temperature of about 25° C. Binding reactions were determined by rapid filtration onto 96-well Unifilter GF/C filter plates (Packard) presoaked in 0.5% polyethylenimine (Sigma-Aldrich). Harvesting was performed using a 96-well tissue harvester (Packard) followed by five filtration washes with 500 μL ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 1-2 hrs. Fifty μL/well scintillation cocktail (MicroScint20, Packard) was added and plates were counted in a Packard Top-Count for 1 min/well.
- Radioligand Binding Assay Radioligand dose-displacement binding assays for μ-opioid receptors used 0.2 nM[3H]-diprenorphine (NEN, Boston, Mass.), with 5-20 mg membrane protein/well in a final volume of 500 μl binding buffer (10 mM MgCl2, 1 mM EDTA, 5% DMSO, 50 mM HEPES, pH 7.4). Reactions were carried out in the absence or presence of increasing concentrations of unlabeled naloxone. All reactions were conducted in 96-deep well polypropylene plates for 1-2 hr at room temperature. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Packard, Meriden, Conn.) presoaked in 0.5% polyethylemimine using a 96-well tissue harvester (Brandel, Gaithersburg, Md.) followed by performing three filtration washes with 500 μl of ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 2-3 hours. BetaScint scintillation cocktail (Wallac, Turku, Finland) was added (50 μl/well), and plates were counted using a Packard Top-Count for 1 min/well.
- Radioligand Dose-Displacement Binding Assay δ-Opioid Receptor Binding Assay Procedures were conducted as follows. Radioligand dose-displacement assays used 0.2 nM [3H]-Naltrindole (Perkin Elmer, Shelton, Conn.; 33.0 Ci/mmole) with 5 μg membrane protein (Perkin Elmer, Shelton, Conn.) in a final volume of 500 μl binding buffer (5 mM MgCl2, 5% DMSO, 50 mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 25 μM unlabeled naloxone. All reactions were performed in 96-deep well polypropylene plates for 1 hour at a temperature of about 25° C. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.) presoaked in 0.5% polyethylenimine (Sigma). Harvesting was performed using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by five filtration washes with 500 μl ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 1-2 hours.
- Radioligand Dose-Displacement Binding Assay δ-opioid Receptor Binding Assay Procedures were conducted as follows. Radioligand dose-displacement assays used 0.3 nM [3H]-Naltrindole (Perkin Elmer, Shelton, Conn.; 33.0 Ci/mmole) with 5 μg membrane protein (Perkin Elmer, Shelton, Conn.) in a final volume of 500 μl binding buffer (5 mM MgCl2, 5% DMSO, 50 mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 25 μM unlabeled naloxone. All reactions were performed in 96-deep well polypropylene plates for 1 hr at a temperature of about 25° C. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.) presoaked in 0.5% polyethylenimine (Sigma). Harvesting was performed using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by five filtration washes with 500 μl ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 1-2 hours.
- Radioligand Dose-Displacement Binding Assay Delta-Opioid Receptor Binding Assay Procedures: delta-Opioid Receptor Binding Assay Procedures were conducted as follows. Radioligand dose-displacement assays used 0.3 nM [3H]-Naltrindole (Perkin Elmer, Shelton, Conn.; 33.0 Ci/mmole) with 5 ug membrane protein (Perkin Elmer, Shelton, Conn.) in a final volume of 500 ul binding buffer (5 mM MgCl2, 5% DMSO, 50 mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 25 uM unlabeled naloxone. All reactions were performed in 96-deep well polypropylene plates for 1 hour at a temperature of about 25 C. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.) presoaked in 0.5% polyethylenimine (Sigma). Harvesting was performed using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by five filtration washes with 500 ul ice-cold binding buffer. Filter plates were subsequently dried at 50 C. for 1-2 hours.
- Radioligand Dose-Displacement Binding Assay Radioligand dose displacement assays used 0.4 nM [3H]-U69,593 (GE Healthcare, Piscataway, N.J.; 40 Ci/mmole) with 15 ug membrane protein (recombinant kippa opioid receptor expressed in HEK 293 cells; in-house prep) in a final volume of 200 ul binding buffer (5% DMSO, 50 mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 10 uM unlabeled naloxone or U69,593. All reactions were performed in 96-well polypropylene plates for 1 hour at a temperature of about 25 C. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.) presoaked in 0.5% polyethylenimine (Sigma). Harvesting was performed using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by five filtration washes with 200 ul ice-cold binding buffer. Filter plates were subsequently dried at 50 C. for 1-2 hours. Fifty ul/well scintillation cocktail (Perkin Elmer, Shelton, Conn.) was added.
- Radioligand Dose-Displacement Binding Assay Radioligand dose displacement assays used 0.4 nM [3]-U69,593 (GE Healthcare, Piscataway, N.J.; 40 Ci/mmole) with 15 ug membrane protein (recombinant kippa opioid receptor expressed in HEK 293 cells; in-house prep) in a final volume of 200 ul binding buffer (5% DMSO, 50 mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 10 uM unlabeled naloxone or U69,593. All reactions were performed in 96-well polypropylene plates for 1 hr at a temperature of about 25 C. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.) presoaked in 0.5% polyethylenimine (Sigma). Harvesting was performed using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by five filtration washes with 200 ul ice-cold binding buffer. Filter plates were subsequently dried at 50 C. for 1-2 hours. Fifty ul/well scintillation cocktail (Perkin Elmer, Shelton, Conn.) was added.
- Radioligand Dose-Displacement Binding Assay Radioligand dose-displacement binding assays for -opioid receptors used 0.3 nM [3H]-diprenorphine (Perkin Elmer, Shelton, Conn.), with 5 mg membrane protein/well in a final volume of 500 ul binding buffer (10 mM MgCl2, 1 mM EDTA, 5% DMSO, 50 mM HEPES, pH 7.4). Reactions were carried out in the absence or presence of increasing concentrations of unlabeled naloxone. All reactions were conducted in 96-deep well polypropylene plates for 2 hr at room temperature. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.), presoaked in 0.5% polyethylenimine using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by performing three filtration washes with 500 ul of ice-cold binding buffer. Filter plates were subsequently dried at 50 C. for 2-3 hours. BetaScint scintillation cocktail (Perkin Elmer, Shelton, Conn.) was added (50 ul/well), and plates were counted using a Packard Top-Count.
- Radioligand Dose-Displacement Binding Assay Radioligand dose-displacement binding assays for mu-opioid receptors used 0.3 nM [3H]-diprenorphine (Perkin Elmer, Shelton, Conn.), with 5 mg membrane protein/well in a final volume of 500 ul binding buffer (10 mM MgCl2, 1 mM EDTA, 5% DMSO, 50 mM HEPES, pH 7.4). Reactions were carried out in the absence or presence of increasing concentrations of unlabeled naloxone. All reactions were conducted in 96-deep well polypropylene plates for 2 hours at room temperature. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.), presoaked in 0.5% polyethylenimine using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by performing three filtration washes with 500 ul of ice-cold binding buffer. Filter plates were subsequently dried at 50 C. for 2-3 hours. BetaScint scintillation cocktail (Perkin Elmer, Shelton, Conn.) was added (50 ul/well), and plates were counted using a Packard Top-Counter.
- Radioligand Dose-Displacement Binding Assay Radioligand dose-displacement binding assays for mu-opioid receptors used 0.3 nM [3H]-diprenorphine (Perkin Elmer, Shelton, Conn.), with 5 mg membrane protein/well in a final volume of 500 ul binding buffer (10 mM MgCl2, 1 mM EDTA, 5% DMSO, 50 mM HEPES, pH 7.4). Reactions were carried out in the absence or presence of increasing concentrations of unlabeled naloxone. All reactions were conducted in 96-deep well polypropylene plates for 2 hr at room temperature. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.), presoaked in 0.5% polyethylenimine using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by performing three filtration washes with 500 ul of ice-cold binding buffer. Filter plates were subsequently dried at 50 C. for 2-3 hours. BetaScint scintillation cocktail (Perkin Elmer, Shelton, Conn.) was added (50 ul/well), and plates were counted using a Packard Top-Count.
- Radioligand Dose-Displacement Binding Assay Radioligand dose-displacement binding assays for t-opioid receptors used 0.3 nM [3H]-diprenorphine (Perkin Elmer, Shelton, Conn.), with 5 mg membrane protein/well in a final volume of 500 ul binding buffer (10 mM MgCl2, 1 mM EDTA, 5% DMSO, 50 mM HEPES, pH 7.4). Reactions were carried out in the absence or presence of increasing concentrations of unlabeled naloxone. All reactions were conducted in 96-deep well polypropylene plates for 2 hr at room temperature. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.), presoaked in 0.5% polyethylenimine using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by performing three filtration washes with 500 ul of ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 2-3 hours. BetaScint scintillation cocktail (Perkin Elmer, Shelton, Conn.) was added (50 ul/well), and plates were counted using a Packard Top-Count.
- Radioligand Dose-Displacement Binding Assay Radioligand dose-displacement binding assays for u-opioid receptors used 0.3 nM [3H]-diprenorphine (Perkin Elmer, Shelton, Conn.), with 5 mg membrane protein/well in a final volume of 500 ul binding buffer (10 mM MgCl2, 1 mM EDTA, 5% DMSO, 50 mM HEPES, pH 7.4). Reactions were carried out in the absence or presence of increasing concentrations of unlabeled naloxone. All reactions were conducted in 96-deep well polypropylene plates for 2 hours at room temperature. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.), presoaked in 0.5% polyethylenimine using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by performing three filtration washes with 500 ul of ice-cold binding buffer. Filter plates were subsequently dried at 50 C. for 2-3 hours. BetaScint scintillation cocktail (Perkin Elmer, Shelton, Conn.) was added (50 ul/well), and plates were counted using a Packard Top-Counter.
- Radioligand Dose-Displacement Binding Assay mu-Opioid Receptor Binding Assay Procedures: Radioligand dose-displacement binding assays for mu-opioid receptors used 0.3 nM [3H]-diprenorphine (Perkin Elmer, Shelton, Conn.), with 5 mg membrane protein/well in a final volume of 500 ul binding buffer (10 mM MgCl2, 1 mM EDTA, 5% DMSO, 50 mM HEPES, pH 7.4). Reactions were carried out in the absence or presence of increasing concentrations of unlabeled naloxone. All reactions were conducted in 96-deep well polypropylene plates for 2 hours at room temperature. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.), presoaked in 0.5% polyethylenimine using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by performing three filtration washes with 500 ul of ice-cold binding buffer. Filter plates were subsequently dried at 50 C. for 2-3 hours. BetaScint scintillation cocktail (Perkin Elmer, Shelton, Conn.) was added (50 ul/well).
- Radioligand Dose-Displacement Binding Assays (mu) Radioligand dose-displacement binding assays for mu-opioid receptors used 0.3 nM [3H]-diprenorphine (Perkin Elmer, Shelton, Conn.), with 5 mg membrane protein/well in a final volume of 500 ul binding buffer (10 mM MgCl2,1 mM EDTA, 5% DMSO, 50 mM HEPES, pH 7.4). Reactions were carried out in the absence or presence of increasing concentrations of unlabeled naloxone. All reactions were conducted in 96-deep well polypropylene plates for 2 hr at room temperature. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.), presoaked in 0.5% polyethylenimine using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by performing three filtration washes with 500 ul of ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 2-3 hours. BetaScint scintillation cocktail (Perkin Elmer, Shelton, Conn.) was added (50 ul/well), and plates were counted using a Packard Top-Count.
- μ-Opioid Receptor Binding Assay Radioligand dose-displacement binding assays for μ-opioid receptors used 0.3 nM [3H]-diprenorphine (Perkin Elmer, Shelton, Conn.), with 5 mg membrane protein/well in a final volume of 500 μl binding buffer (10 mM MgCl2, 1 mM EDTA, 5% DMSO, 50 mM HEPES, pH 7.4). Reactions were carried out in the absence or presence of increasing concentrations of unlabeled naloxone. All reactions were conducted in 96-deep well polypropylene plates for 2 hours at room temperature. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.), presoaked in 0.5% polyethylenimine using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by performing three filtration washes with 500 μl of ice-cold binding buffer. Filter plates were subsequently dried at 50 °C. for 2-3 hours. BetaScint scintillation cocktail (Perkin Elmer, Shelton, Conn.) was added (50 μl/well), and plates were counted using a Packard Top-Count for 1 min/well.
- μ-opioid Receptor Binding Assay Radioligand dose-displacement binding assays for μ-opioid receptors used 0.2 nM[3H]-diprenorphine (NEN, Boston, Mass.), with 5-20 mg membrane protein/well in a final volume of 500 μL binding buffer (10 mM MgCl2, 1 mM EDTA, 5% DMSO, 50 mM HEPES, pH 7.4). Reactions were carried out in the absence or presence of increasing concentrations of unlabeled naloxone. All reactions were conducted in 96-deep well polypropylene plates for 1-2 hr at about 25° C. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Packard, Meriden, Conn.) presoaked in 0.5% polyethylenimine using a 96-well tissue harvester (Brandel, Gaithersburg, Md.) followed by performing three filtration washes with 500 μL of ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 2-3 hours. BetaScint scintillation cocktail (Wallac, Turku, Finland) was added (50 μL/well), and plates were counted using a Packard Top-Count for 1 min/well.
- Competitive Displacement Assay Membrane protein from CHO (Chinese Hamster Ovarian) cells that stably expressed one type of the cloned human opioid receptor were incubated with 12 different concentrations of the compound in the presence of 0.25 nM [3H]DAMGO, 0.2 nM [3H]naltrindole or 1 nM [3H]U69,593 in a final volume of 1 mL of 50 mM Tris-HCl, pH 7.5 at 25° C. Incubation times of 60 min were used for [3H]DAMGO and [3H]U69,593. Because of a slower association of [3H]naltrindole with the receptor, a 3 h incubation was used with this radioligand. Samples incubated with [3H]naltrindole also contained 10 mM MgCl2 and 0.5 mM phenylmethylsulfonyl fluoride. Nonspecific binding was measured by inclusion of 10 μM naloxone. The binding was terminated by filtering the samples through Schleicher & Schuell No. 32 glass fiber filters using a Brandel 48-well cell harvester. The filters were subsequently washed three times with 3 mL of cold 50 mM Tris-HCl, pH 7.5, and were counted in 2 mL Ecoscint A scintillation fluid. For [3H]naltrindole and [3H]U69,593 binding, the filters were soaked in 0.1% polyethylenimine for at least 60 min before use.
- In Vitro Delta-Opioid Receptor Binding Assay δ-Opioid Receptor Binding Assay Procedures: Radioligand dose-displacement assays used 0.2 nM [3H]-Naltrindole (NEN; 33.0 Ci/mmole) with 10-20 μg membrane protein (recombinant delta opioid receptor expressed in CHO-K1 cells; Perkin Elmer) in a final volume of 500 μL binding buffer (5 mM MgCl2, 5% DMSO, 50 mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 25 μM unlabeled naloxone. All reactions were performed in 96-deep well polypropylene plates for 1 h at a temperature of about 25° C. Binding reactions were determined by rapid filtration onto 96-well Unifilter GF/C filter plates (Packard) presoaked in 0.5% polyethylenimine (Sigma-Aldrich). Harvesting was performed using a 96-well tissue harvester (Packard) followed by five filtration washes with 500 μL ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 1-2 hours. Fifty μL/well scintillation cocktail (MicroScint20, Packard) was added and plates were counted in a Packard Top-Count for 1 min/well.
- In Vitro Delta-Opioid Receptor Binding Assay δ-Opioid Receptor Binding Assay Procedures: Radioligand dose-displacement assays used 0.2 nM [3H]-Naltrindole (NEN; 33.0 Ci/mmole) with 10-20 μg membrane protein (recombinant delta opioid receptor expressed in CHO-K1 cells; Perkin Elmer) in a final volume of 500 μL binding buffer (5 mM MgCl2, 5% DMSO, 50 mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 25 μM unlabeled naloxone. All reactions were performed in 96-deep well polypropylene plates for 1 h at a temperature of about 25° C. Binding reactions were determined by rapid filtration onto 96-well Unifilter GF/C filter plates (Packard) presoaked in 0.5% polyethylenimine (Sigma-Aldrich). Harvesting was performed using a 96-well tissue harvester (Packard) followed by five filtration washes with 500 μL ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 1-2 hrs. Fifty μL/well scintillation cocktail (MicroScint20, Packard) was added and plates were counted in a Packard Top-Count for 1 min/well.
- In Vitro Delta-Opioid Receptor Binding Assay Radioligand dose-displacement assays used 0.2 nM [3H]-Naltrindole (NEN; 33.0 Ci/mmole) with 10-20 μg membrane protein (recombinant delta opioid receptor expressed in CHO-K1 cells; Perkin Elmer) in a final volume of 500 μL binding buffer (5 mM MgCl2, 5% DMSO, 50 mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 25 μM unlabeled naloxone. All reactions were performed in 96-deep well polypropylene plates for 1 h at a temperature of about 25 °C. Binding reactions were determined by rapid filtration onto 96-well Unifilter GF/C filter plates (Packard) presoaked in 0.5% polyethylenimine (Sigma-Aldrich). Harvesting was performed using a 96-well tissue harvester (Packard) followed by five filtration washes with 500 μL ice-cold binding buffer. Filter plates were subsequently dried at 50 °C. for 1-2 hours. Fifty μL/well scintillation cocktail (MicroScint20, Packard) was added and plates were counted in a Packard Top-Count for 1 min/well.
- In Vitro Kappa-Opioid Receptor Binding Assay Radioligand dose displacement assays used 0.4-0.8 nM [3H]-U69,593 (NEN; 40 Ci/mmole) with 10-20 μg membrane protein (recombinant kappa opioid receptor expressed in HEK 293 cells; in-house prep) in a final volume of 200 μL binding buffer (5% DMSO, 50 mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 10 μM unlabeled naloxone or U69,593. All reactions were performed in 96-well polypropylene plates for 1 h at a temperature of about 25 °C. Binding reactions were determined by rapid filtration onto 96-well Unifilter GF/C filter plates (Packard) presoaked in 0.5% polyethylenimine (Sigma-Aldrich). Harvesting was performed using a 96-well tissue harvester (Packard) followed by five filtration washes with 200 μL ice-cold binding buffer. Filter plates were subsequently dried at 50 °C. for 1-2 hours. Fifty μL/well scintillation cocktail (MicroScint20, Packard) was added and plates were counted in a Packard Top-Count for 1 min/well.
- Radioligand dose displacement assay κ-Opioid: Radioligand dose displacement assays used 0.4 nM [3H]-U69,593 (GE Healthcare, Piscataway, N.J.; 40 Ci/mmole) with 15 μg membrane protein (recombinant κ opioid receptor expressed in HEK 293 cells; in-house prep) in a final volume of 200 μl binding buffer (5% DMSO, 50 mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 10 μM unlabeled naloxone or U69,593. All reactions were performed in 96-well polypropylene plates for 1 hour at a temperature of about 25° C. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.) presoaked in 0.5% polyethylenimine (Sigma). Harvesting was performed using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by five filtration washes with 200 μl ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 1-2 hours. Fifty μl/well scintillation cocktail (Perkin Elmer, Shelton, Conn.) was added and plates were counted in a Packard Top-Count for 1 min/well.
- Radioligand dose-Displacement Binding Assay Radioligand dose-displacement binding assays for μ-opioid receptors used 0.3 nM [3H]-diprenorphine (Perkin Elmer, Shelton, Conn.), with 5 mg membrane protein/well in a final volume of 500 μl binding buffer (10 mM MgCl2, 1 mM EDTA, 5% DMSO, 50 mM HEPES, pH 7.4). Reactions were carried out in the absence or presence of increasing concentrations of unlabeled naloxone. All reactions were conducted in 96-deep well polypropylene plates for 2 hours at room temperature. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.), presoaked in 0.5% polyethylenimine using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by performing three filtration washes with 500 μl of ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 2-3 hours. BetaScint scintillation cocktail (Perkin Elmer, Shelton, Conn.) was added (50 μl/well), and plates were counted using a Packard Top-Count for 1 min/well.
- kappa-Opioid Receptor Binding Assay Radioligand dose displacement assays used 0.4 nM [3H]-U69,593 (GE Healthcare, Piscataway, N.J.; 40 Ci/mmole) with 15 μg membrane protein (recombinant κ opioid receptor expressed in HEK 293 cells; in-house prep) in a final volume of 200 μl binding buffer (5% DMSO, 50 mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 10 μM unlabeled naloxone or U69,593. All reactions were performed in 96-well polypropylene plates for 1 hour at a temperature of about 25° C. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.) presoaked in 0.5% polyethylenimine (Sigma). Harvesting was performed using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by five filtration washes with 200 μl ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 1-2 hours. Fifty μl/well scintillation cocktail (Perkin Elmer, Shelton, Conn.) was added and plates were counted in a Packard Top-Count for 1 min/well.
- κ-Opioid Receptor Binding Assay Radioligand dose displacement assays used 0.4 nM [3H]-U69,593 (GE Healthcare, Piscataway, N.J.; 40 Ci/mmole) with 15 μg membrane protein (recombinant κ opioid receptor expressed in HEK 293 cells; in-house prep) in a final volume of 200 μl binding buffer (5% DMSO, 50 mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 10 μM unlabeled naloxone or U69,593. All reactions were performed in 96-well polypropylene plates for 1 hour at a temperature of about 25 °C. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.) presoaked in 0.5% polyethylenimine (Sigma). Harvesting was performed using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by five filtration washes with 200 μl ice-cold binding buffer. Filter plates were subsequently dried at 50 °C. for 1-2 hours. Fifty μl/well scintillation cocktail (Perkin Elmer, Shelton, Conn.) was added and plates were counted in a Packard Top-Count for 1 min/well.
- In Vitro Mu-Opioid Receptor Binding Assay Radioligand binding assays were conducted using freshly thawed membranes expressing human μ-receptors (Perkin Elmer, Shelton, Conn.). Radioligand dose-displacement binding assays for human μ-opioid receptors used 0.2 nM [3H]-diprenorphine (NEN, Boston, Mass.), with 5-20 mg membrane protein/well in a final volume of 500 μL binding buffer (10 mM MgCl2, 1 mM EDTA, 5% DMSO, 50 mM HEPES, pH 7.4). Reactions were carried out in the absence or presence of increasing concentrations of unlabeled naloxone. All reactions were conducted in 96-deep well polypropylene plates for 1-2 hr at about 25 °C. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Packard, Meriden, Conn.) presoaked in 0.5% polyethylenimine using a 96-well tissue harvester (Brandel, Gaithersburg, Md.) followed by performing three filtration washes with 500 μL of ice-cold binding buffer. Filter plates were subsequently dried at 50 °C. for 2-3 hours. BetaScint scintillation cocktail (Wallac, Turku, Finland) was added (50 μL/well), and plates were counted using a Packard Top-Count for 1 min/well.
- Opioid Receptor Binding Assay The Ki (binding affinity) for μ opioid receptors was determined using a competitive displacement assay as previously described in Neumeyer (Journal of Med. Chem. 2012, p 3878), which is incorporated herein in its entirety. Briefly, membrane protein from CHO (Chinese Hamster Ovarian) cells that stably expressed the cloned human μ opioid receptor were incubated with 12 different concentrations of the compound set forth herein in the presence of 0.25 nM [3H]DAMGO (see Tiberi et al., Can. J. Physiol. Pharmacol. 1988, Vol. 66, p 1368, which is incorporated by reference herein in its entirety) in a final volume of 1 mL of 50 mM Tris-HCl, pH 7.5 at 25° C. Incubation times of 60 min were used for [3H]DAMGO (see Gulati et al., Life Sci. 1990, Vol. 47, p 159, which is incorporated by reference herein in its entirety). Nonspecific binding was measured by inclusion of 10 μM naloxone. The binding was terminated by filtering the samples through Schleicher & Schuell No. 32 glass fiber filters using a Brandel 48-well cell harvester. The filters were subsequently washed three times with 3 mL of cold 50 mM Tris-HCl, pH 7.5, and were counted in 2 mL Ecoscint A scintillation fluid.
- Radioligand dose-Displacement Binding Assay Radioligand dose displacement assays used 0.4 nM [3H]-U69,593 (GE Healthcare, Piscataway, N.J.; 40 Ci/mmole) with 15 μg membrane protein (recombinant κ opioid receptor expressed in HEK 293 cells; in-house prep) in a final volume of 200 μl binding buffer (5% DMSO, 50 mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 10 μM unlabeled naloxone or U69,593. All reactions were performed in 96-well polypropylene plates for 1 hour at a temperature of about 25° C. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.) presoaked in 0.5% polyethylenimine (Sigma). Harvesting was performed using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by five filtration washes with 200 μl ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 1-2 hours. Fifty μl/well scintillation cocktail (Perkin Elmer, Shelton, Conn.) was added and plates were counted in a Packard Top-Count for 1 min/well.
- Radioligand dose-displacement Binding Assay κ-Opioid: Radioligand dose displacement assays used 0.4 nM [3H]-U69,593 (GE Healthcare, Piscataway, N.J.; 40 Ci/mmole) with 15 μg membrane protein (recombinant κ opioid receptor expressed in HEK 293 cells; in-house prep) in a final volume of 200 μl binding buffer (5% DMSO, 50 mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 10 μM unlabeled naloxone or U69,593. All reactions were performed in 96-well polypropylene plates for 1 hour at a temperature of about 25° C. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.) presoaked in 0.5% polyethylenimine (Sigma). Harvesting was performed using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by five filtration washes with 200 μl ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 1-2 hours. Fifty μl/well scintillation cocktail (Perkin Elmer, Shelton, Conn.) was added and plates were counted in a Packard Top-Count for 1 min/well.
- Radioligand dose-displacement binding assay μ-opioid receptors used 0.3 nM [3H]-diprenorphine (Perkin Elmer, Shelton, Conn.), with 5 mg membrane protein/well in a final volume of 500 μl binding buffer (10 mM MgCl2, 1 mM EDTA, 5% DMSO, 50 mM HEPES, pH 7.4). Reactions were carried out in the absence or presence of increasing concentrations of unlabeled naloxone. All reactions were conducted in 96-deep well polypropylene plates for 2 hours at room temperature. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.), presoaked in 0.5% polyethylenimine using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by performing three filtration washes with 500 μl of ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 2-3 hours. BetaScint scintillation cocktail (Perkin Elmer, Shelton, Conn.) was added (50 μl/well), and plates were counted using a Packard Top-Count for 1 min/well. The data were analyzed using the one-site competition curve fitting functions in GraphPad PRISM v. 3.0 or higher (San Diego, Calif.), or an in-house function for one-site competition curve-fitting.
- μ-Opioid Receptor Binding Assay Radioligand dose-displacement binding assays for μ-opioid receptors used 0.3 nM [3H]-diprenorphine (Perkin Elmer, Shelton, Conn.), with 5 mg membrane protein/well in a final volume of 500 μl binding buffer (10 mM MgCl2, 1 mM EDTA, 5% DMSO, 50 mM HEPES, pH 7.4). Reactions were carried out in the absence or presence of increasing concentrations of unlabeled naloxone. All reactions were conducted in 96-deep well polypropylene plates for 2 hours at room temperature. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.), presoaked in 0.5% polyethylenimine using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by performing three filtration washes with 500 μl of ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 2-3 hours. BetaScint scintillation cocktail (Perkin Elmer, Shelton, Conn.) was added (50 μl/well), and plates were counted using a Packard Top-Count for 1 min/well. The data were analyzed using the one-site competition curve fitting functions in GraphPad PRISM v. 3.0 or higher (San Diego, Calif.), or an in-house function for one-site competition curve-fitting.
- Mu-Opioid Receptor Binding Assay Radioligand dose-displacement binding assays for μ-opioid receptors can use 0.3 nM [3H]-diprenorphine (Perkin Elmer, Shelton, CT), with 5 mg membrane protein/well in a final volume of 500 μl binding buffer (10 mM MgCl2, 1 mM EDTA, 5% DMSO, 50 mM HEPES, pH 7.4). Reactions are carried out in the absence or presence of increasing concentrations of unlabeled naloxone. All reactions are conducted in 96-deep well polypropylene plates for 2 hours at room temperature. Binding reactions are terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, CT), presoaked in 0.5% polyethylenimine using a 96-well tissue harvester (Perkin Elmer, Shelton, CT) followed by performing three filtration washes with 500 μl of ice-cold binding buffer. Filter plates are subsequently dried at 50 C. for 2-3 hours. BetaScint scintillation cocktail (Perkin Elmer, Shelton, CT) is added (50 μl/well), and plates are counted using a Packard Top-Count for 1 min/well. The data are analyzed using the one-site competition curve fitting functions in GraphPad PRISM v. 3.0 or higher (San Diego, Calif.), or an in-house function for one-site competition curve-fitting. Data are expressed as mean S.E.M. The results are represented as inhibition constants, Ki values (the concentration of a compound that produces half maximal inhibition).
- Mu-Opioid Receptor Binding Assay Radioligand dose-displacement binding assays for μ-opioid receptors used 0.3 nM [3H]-diprenorphine (Perkin Elmer, Shelton, Conn.), with 5 mg membrane protein/well in a final volume of 500 μl binding buffer (10 mM MgCl2, 1 mM EDTA, 5% DMSO, 50 mM HEPES, pH 7.4). Reactions were carried out in the absence or presence of increasing concentrations of unlabeled naloxone. All reactions were conducted in 96-deep well polypropylene plates for 2 hours at room temperature. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.), presoaked in 0.5% polyethylenimine using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by performing three filtration washes with 500 μl of ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 2-3 hours. BetaScint scintillation cocktail (Perkin Elmer, Shelton, Conn.) was added (50 μl/well), and plates were counted using a Packard Top-Count for 1 min/well. The data were analyzed using the one-site competition curve fitting functions in GraphPad PRISM v. 3.0 or higher (San Diego, Calif.), or an in-house function for one-site competition curve-fitting.
- Radioligand dose-displacement Binding Assay μ-Opioid Receptor:Radioligand dose-displacement binding assays for μ-opioid receptors used 0.3 nM [3H]-diprenorphine (Perkin Elmer, Shelton, Conn.), with 5 mg membrane protein/well in a final volume of 500 μl binding buffer (10 mM MgCl2, 1 mM EDTA, 5% DMSO, 50 mM HEPES, pH 7.4). Reactions were carried out in the absence or presence of increasing concentrations of unlabeled naloxone. All reactions were conducted in 96-deep well polypropylene plates for 2 hours at room temperature. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.), presoaked in 0.5% polyethylenimine using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by performing three filtration washes with 500 μl of ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 2-3 hours. BetaScint scintillation cocktail (Perkin Elmer, Shelton, Conn.) was added (50 μl/well), and plates were counted using a Packard Top-Count for 1 min/well. The data were analyzed using the one-site competition curve fitting functions in GraphPad PRISM v. 3.0 or higher (San Diego, Calif.), or an in-house function for one-site competition curve-fitting.
- Receptor Binding Assay μ-Opioid: Radioligand dose-displacement binding assays for μ-opioid receptors used 0.3 nM [3H]-diprenorphine (Perkin Elmer, Shelton, Conn.), with 5 mg membrane protein/well in a final volume of 500 μl binding buffer (10 mM MgCl2, 1 mM EDTA, 5% DMSO, 50 mM HEPES, pH 7.4). Reactions were carried out in the absence or presence of increasing concentrations of unlabeled naloxone. All reactions were conducted in 96-deep well polypropylene plates for 2 hr at room temperature. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.), presoaked in 0.5% polyethylenimine using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by performing three filtration washes with 500 μl of ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 2-3 hours. BetaScint scintillation cocktail (Perkin Elmer, Shelton, Conn.) was added (50 μl/well), and plates were counted using a Packard Top-Count for 1 min/well. The data were analyzed using the one-site competition curve fitting functions in GraphPad PRISM v. 3.0 or higher (San Diego, Calif.), or an in-house function for one-site competition curve-fitting.
- Receptor Binding Assay μ-Opioid:Radioligand dose-displacement binding assays for μ-opioid receptors used 0.3 nM [3H]-diprenorphine (Perkin Elmer, Shelton, Conn.), with 5 mg membrane protein/well in a final volume of 500 μl binding buffer (10 mM MgCl2, 1 mM EDTA, 5% DMSO, 50 mM HEPES, pH 7.4). Reactions were carried out in the absence or presence of increasing concentrations of unlabeled naloxone. All reactions were conducted in 96-deep well polypropylene plates for 2 hours at room temperature. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.), presoaked in 0.5% polyethylenimine using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by performing three filtration washes with 500 μl of ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 2-3 hours. BetaScint scintillation cocktail (Perkin Elmer, Shelton, Conn.) was added (50 μl/well), and plates were counted using a Packard Top-Count for 1 min/well. The data were analyzed using the one-site competition curve fitting functions in GraphPad PRISM v. 3.0 or higher (San Diego, Calif.), or an in-house function for one-site competition curve-fitting.
- Receptor Binding of PEG-Nalbuphine Conjugates Briefly, the receptor binding affinity of the nalbuphine and PEG-nalbuphine conjugates was measured using radioligand binding assays in CHO cells that heterologously express the recombinant human mu, delta or the kappa opioid receptor. Cells were plated in 24 well plates at a density of 0.2-0.3*106 cells/well and washed with assay buffer containing 50 mM Tris.HCl and 5 mM MgCl2 (pH 7.4). Competition binding assays were conducted in whole cells incubated with increasing concentrations of test compounds in the presence of appropriate concentration of radioligand. 0.5 nM 3H Naloxone, 0.5 nM 3H Diprenorphine and 0.5 nM 3H DPDPE were used as the competing radioligands for mu, kappa and delta receptors respectively. Incubations were carried out for two hours at room temperature using triplicate wells at each concentration. At the end of the incubation, cells were washed with 50 mM Tris HCl (pH 8.0), solubilized with NaOH and bound radioactivity was measured using a scintillation counter.Specific binding is determined by subtraction of the cpm bound in the presence of 50-100× excess of cold ligand. Binding data assays were analyzed using GraphPad Prism 4.0 and IC50 is generated by non-linear regression from dose-response curves. Ki values were calculated using the Cheng Prusoff equation using the Kd values from saturation isotherms as follows: Ki=IC50/(1+[Ligand]/Kd).
- mu-Opioid Receptor Binding Assay Radioligand dose-displacement binding assays for μ-opioid receptors used 0.3 nM [3H]-diprenorphine (Perkin Elmer, Shelton, Conn.), with 5 mg membrane protein/well in a final volume of 500 μl binding buffer (10 mM MgCl2, 1 mM EDTA, 5% DMSO, 50 mM HEPES, pH 7.4). Reactions were carried out in the absence or presence of increasing concentrations of unlabeled naloxone. All reactions were conducted in 96-deep well polypropylene plates for 2 hours at room temperature. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.), presoaked in 0.5% polyethylenimine using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by performing three filtration washes with 500 μl of ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 2-3 hours. BetaScint scintillation cocktail (Perkin Elmer, Shelton, Conn.) was added (50 μl/well), and plates were counted using a Packard Top-Count for 1 min/well. The data were analyzed using the one-site competition curve fitting functions in GraphPad PRISM v. 3.0 or higher (San Diego, Calif.), or an in-house function for one-site competition curve-fitting.
- In Vitro Mu-Opioid Receptor Binding Assay μ-Opioid Receptor Binding Assay Procedures: Radioligand binding assays were conducted using freshly thawed membranes expressing human μ-receptors (Perkin Elmer, Shelton, Conn.). Radioligand dose-displacement binding assays for human μ-opioid receptors used 0.2 nM [3H]-diprenorphine (NEN, Boston, Mass.), with 5-20 mg membrane protein/well in a final volume of 500 μL, binding buffer (10 mM MgCl2, 1 mM EDTA, 5% DMSO, 50 mM HEPES, pH 7.4). Reactions were carried out in the absence or presence of increasing concentrations of unlabeled naloxone. All reactions were conducted in 96-deep well polypropylene plates for 1-2 hrs at about 25° C. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Packard, Meriden, Conn.) presoaked in 0.5% polyethylenimine using a 96-well tissue harvester (Brandel, Gaithersburg, Md.) followed by performing three filtration washes with 5004 of ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 2-3 hrs. BetaScint scintillation cocktail (Wallac, Turku, Finland) was added (50 μL/well), and plates were counted using a Packard Top-Count for 1 min/well. The data were analyzed using the one-site competition curve fitting functions in GraphPad PRISM v. 3.0 (San Diego, Calif.), or an in-house function for one-site competition curve-fitting. for 1 min/well.
- In Vitro Mu-Opioid Receptor Binding Assay μ-Opioid Receptor Binding Assay Procedures: Radioligand binding assays were conducted using freshly thawed membranes expressing human μ-receptors (Perkin Elmer, Shelton, Conn.). Radioligand dose-displacement binding assays for human μ-opioid receptors used 0.2 nM[3H]-diprenorphine (NEN, Boston, Mass.), with 5-20 mg membrane protein/well in a final volume of 500 μL binding buffer (10 mM MgCl2, 1 mM EDTA, 5% DMSO, 50 mM HEPES, pH 7.4). Reactions were carried out in the absence or presence of increasing concentrations of unlabeled naloxone. All reactions were conducted in 96-deep well polypropylene plates for 1-2 hr at about 25° C. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Packard, Meriden, Conn.) presoaked in 0.5% polyethylenimine using a 96-well tissue harvester (Brandel, Gaithersburg, Md.) followed by performing three filtration washes with 500 μL of ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 2-3 hours. BetaScint scintillation cocktail (Wallac, Turku, Finland) was added (50 μL/well), and plates were counted using a Packard Top-Count for 1 min/well. The data were analyzed using the one-site competition curve fitting functions in GraphPad PRISM v. 3.0 (San Diego, Calif.), or an in-house function for one-site competition curve-fitting.
- Opioid Receptor Binding Assay The Ki (binding affinity) for μ opioid receptors was determined using a competitive displacement assay as previously described in Neumeyer (Journal of Med. Chem. 2012, p 3878), which is incorporated herein in its entirety. Briefly, membrane protein from CHO (Chinese Hamster Ovarian) cells that stably expressed the cloned human μ opioid receptor were incubated with 12 different concentrations of the compound set forth herein in the presence of 0.25 nM [3H]DAMGO (see Tiberi et al., Can. J. Physiol. Pharmacol. 1988, Vol. 66, p 1368, which is incorporated by reference herein in its entirety) in a final volume of 1 mL of 50 mM Tris-HCl, pH 7.5 at 25° C. Incubation times of 60 min were used for [3H]DAMGO (see Gulati et al., Life Sci. 1990, Vol. 47, p 159, which is incorporated by reference herein in its entirety). Nonspecific binding was measured by inclusion of 10 μM naloxone. The binding was terminated by filtering the samples through Schleicher & Schuell No. 32 glass fiber filters using a Brandel 48-well cell harvester. The filters were subsequently washed three times with 3 mL of cold 50 mM Tris-HCl, pH 7.5, and were counted in 2 mL Ecoscint A scintillation fluid. IC50 values were calculated by least squares fit to a logarithm-probit analysis. Ki values of unlabelled compounds were calculated from the equation Ki=(IC50)/1+S where S=(concentration of radioligand)/(Kd of radioligand) (Cheng and Prusoff, 1973).
- Opioid Receptor Binding Assay The Ki (binding affinity) for μ opioid receptors was determined using a competitive displacement assay as previously described in Neumeyer (Journal of Med. Chem. 2012, p3878), which is incorporated herein in its entirety. Briefly, membrane protein from CHO (Chinese Hamster Ovarian) cells that stably expressed the cloned human μ opioid receptor were incubated with 12 different concentrations of the compound set forth herein in the presence of 0.25 nM [3H]DAMGO (see Tiberi et al., Can. J. Physiol. Pharmacol. 1988, Vol. 66, p1368, which is incorporated by reference herein in its entirety) in a final volume of 1 mL of 50 mM Tris-HCl, pH 7.5 at 25° C. Incubation times of 60 min were used for [3H]DAMGO (see Gulati et al., Life Sci. 1990, Vol. 47, p 159, which is incorporated by reference herein in its entirety). Nonspecific binding was measured by inclusion of 10 μM naloxone. The binding was terminated by filtering the samples through Schleicher & Schuell No. 32 glass fiber filters using a Brandel 48-well cell harvester. The filters were subsequently washed three times with 3 mL of cold 50 mM Tris-HCl, pH 7.5, and were counted in 2 mL Ecoscint A scintillation fluid. IC50 values were calculated by least squares fit to a logarithm-probit analysis. Ki values of unlabelled compounds were calculated from the equation Ki=(IC50)/1+S where S=(concentration of radioligand)/(Kd of radioligand) (Cheng and Prusoff, 1973).
- Opioid Receptor Binding Assay The Ki (binding affinity) for opioid receptors was determined using a competitive displacement assay as previously described in Neumeyer (Journal of Med. Chem. 2012, p 3878), which is incorporated herein in its entirety. Briefly, membrane protein from CHO (Chinese Hamster Ovarian) cells that stably expressed the cloned human μ opioid receptor were incubated with 12 different concentrations of the compound set forth herein in the presence of 0.25 nM [3H]DAMGO (see Tiberi et al., Can. J. Physiol. Pharmacol. 1988, Vol. 66, p 1368, which is incorporated by reference herein in its entirety) in a final volume of 1 mL of 50 mM Tris-HCl, pH 7.5 at 25° C. Incubation times of 60 min were used for [3H]DAMGO (see Gulati et al., Life Sci. 1990, Vol. 47, p 159, which is incorporated by reference herein in its entirety). Nonspecific binding was measured by inclusion of 10 μM naloxone. The binding was terminated by filtering the samples through Schleicher & Schuell No. 32 glass fiber filters using a Brandel 48-well cell harvester. The filters were subsequently washed three times with 3 mL of cold 50 mM Tris-HCl, pH 7.5, and were counted in 2 mL Ecoscint A scintillation fluid. IC50 values were calculated by least squares fit to a logarithm-probit analysis. Ki values of unlabelled compounds were calculated from the equation Ki=(IC50)/1+S where S=(concentration of radioligand)/(Kd of radioligand) (Cheng and Prusoff, 1973).
- Opioid Receptor Binding Assay The Ki (binding affinity) for opioid receptors was determined using a competitive displacement assay as previously described in Neumeyer (Journal of Med. Chem. 2012, p 3878), which is incorporated herein in its entirety. Briefly, membrane protein from CHO (Chinese Hamster Ovarian) cells that stably expressed the cloned human opioid receptor were incubated with 12 different concentrations of the compound set forth herein in the presence of 0.25 nM [3H]DAMGO (see Tiberi et al., Can. J. Physiol. Pharmacol. 1988, Vol. 66, p 1368, which is incorporated by reference herein in its entirety) in a final volume of 1 mL of 50 mM Tris-HCl, pH 7.5 at 25° C. Incubation times of 60 min were used for [3H]DAMGO (see Gulati et al., Life Sci. 1990, Vol. 47, p 159, which is incorporated by reference herein in its entirety). Nonspecific binding was measured by inclusion of 10 M naloxone. The binding was terminated by filtering the samples through Schleicher & Schuell No. 32 glass fiber filters using a Brandel 48-well cell harvester. The filters were subsequently washed three times with 3 mL of cold 50 mM Tris-HCl, pH 7.5, and were counted in 2 mL Ecoscint A scintillation fluid. IC50 values were calculated by least squares fit to a logarithm-probit analysis. Ki values of unlabelled compounds were calculated from the equation Ki=(IC50)/1+S where S=(concentration of radioligand)/(Kd of radioligand) (Cheng and Prusoff, 1973).
- Receptor Binding Assay The Ki (binding affinity) for μ-receptor was determined with a previously described method using a competitive displacement assay (Neumeyer et al., J. Med. Chem., v. 46, p. 5162-5170, 2003). Membrane protein from CHO (Chinese Hamster Ovarian) cells that stably expressed one type of the cloned human opioid receptor were incubated with 12 different concentrations of the compound in the presence of 0.25 nM [3H]DAMGO, 0.2 nM [3H]naltrindole or 1 nM [3H]U69,593 in a final volume of 1 mL of 50 mM Tris-HCl, pH 7.5 at 25° C. Incubation times of 60 min were used for [3H]DAMGO and [3H]U69,593. Because of a slower association of [3H]naltrindole with the receptor, a 3 h incubation was used with this radioligand. Samples incubated with [3H]naltrindole also contained 10 mM MgCl2 and 0.5 mM phenylmethylsulfonyl fluoride. Nonspecific binding was measured by inclusion of 10 μM naloxone. The binding was terminated by filtering the samples through Schleicher & Schuell No. 32 glass fiber filters using a Brandel 48-well cell harvester. The filters were subsequently washed three times with 3 mL of cold 50 mM Tris-HCl, pH 7.5, and were counted in 2 mL Ecoscint A scintillation fluid. For [3H]naltrindole and [3H]U69,593 binding, the filters were soaked in 0.1% polyethylenimine for at least 60 min before use. IC50 values will be calculated by least squares fit to a logarithm-probit analysis. Ki values of unlabelled compounds were calculated from the equation Ki=(IC50)/1+S where S=(concentration of radioligand)/(Kd of radioligand).
- In Vitro Kappa-Opioid Receptor Binding Assay κ-Opioid Receptor Binding Assay Procedures: Membranes from recombinant HEK-293 cells expressing the human kappa opioid receptor (kappa) (cloned in house) were prepared by lysing cells in ice cold hypotonic buffer (2.5 mM MgCl2, 50 mM HEPES, pH 7.4) (10 mL/10 cm dish) followed by homogenization with a tissue grinder/Teflon pestle. Membranes were collected by centrifugation at 30,000×g for 15 min at 4° C. and pellets resuspended in hypotonic buffer to a final concentration of 1-3 mg/mL. Protein concentrations were determined using the BioRad protein assay reagent with bovine serum albumen as a standard. Aliquots of kappa receptor membranes were stored at −80° C.Radioligand dose displacement assays used 0.4-0.8 nM [3H]-U69,593 (NEN; 40 Ci/mmole) with 10-20 μg membrane protein (recombinant kappa opioid receptor expressed in HEK 293 cells; in-house prep) in a final volume of 200 μL, binding buffer (5% DMSO, 50 mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 10 μM unlabeled naloxone or U69,593. All reactions were performed in 96-well polypropylene plates for 1 h at a temperature of about 25° C. Binding reactions were determined by rapid filtration onto 96-well Unifilter GF/C filter plates (Packard) presoaked in 0.5% polyethylenimine (Sigma-Aldrich). Harvesting was performed using a 96-well tissue harvester (Packard) followed by five filtration washes with 200 μL, ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 1-2 hrs. Fifty μL/well scintillation cocktail (MicroScint20, Packard) was added and plates were counted in a Packard Top-Count for 1 min/well.
- In Vitro Kappa-Opioid Receptor Binding Assay κ-Opioid Receptor Binding Assay Procedures: Membranes from recombinant HEK-293 cells expressing the human kappa opioid receptor (kappa) (cloned in house) were prepared by lysing cells in ice cold hypotonic buffer (2.5 mM MgCl2, 50 mM HEPES, pH 7.4) (10 mL/10 cm dish) followed by homogenization with a tissue grinder/Teflon pestle. Membranes were collected by centrifugation at 30,000×g for 15 min at 4° C. and pellets resuspended in hypotonic buffer to a final concentration of 1-3 mg/mL. Protein concentrations were determined using the BioRad protein assay reagent with bovine serum albumen as a standard. Aliquots of kappa receptor membranes were stored at −80° C. Radioligand dose displacement assays used 0.4-0.8 nM [3H]-U69,593 (NEN; 40 Ci/mmole) with 10-20 μg membrane protein (recombinant kappa opioid receptor expressed in HEK 293 cells; in-house prep) in a final volume of 200 L binding buffer (5% DMSO, 50 mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 10 μM unlabeled naloxone or U69,593. All reactions were performed in 96-well polypropylene plates for 1 h at a temperature of about 25° C. Binding reactions were determined by rapid filtration onto 96-well Unifilter GF/C filter plates (Packard) presoaked in 0.5% polyethylenimine (Sigma-Aldrich). Harvesting was performed using a 96-well tissue harvester (Packard) followed by five filtration washes with 200 μL ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 1-2 hours. Fifty μL/well scintillation cocktail (MicroScint20, Packard) was added and plates were counted in a Packard Top-Count for 1 min/well.
- kappa-Opioid Receptor Binding Assay Membranes from recombinantHEK-293 cells, CHO or U-2 OS cells expressing the recombinant human κ opioid receptor (κ) were prepared by lysing cells in ice cold hypotonic buffer (2.5 mM MgCl2, 50 mM HEPES, pH 7.4) (10 mL/10 cm dish) followed by homogenization with a tissue grinder/Teflon pestle. Membranes were collected by centrifugation at 30,000×g for 15 min at 4° C. and pellets were resuspended in hypotonic buffer to a final concentration of 1-3 mg/mL. Protein concentrations were determined using the BioRad protein assay reagent with bovine serum albumen as standard. Aliquots of κ receptor membranes were stored at −80° C.Radioligand dose displacement assays used 0.4 nM [3H]-U69,593 (GE Healthcare, Piscataway, N.J.; 40 Ci/mmole) with 15 μg membrane protein (recombinant κ opioid receptor expressed in HEK 293 cells; in-house prep) in a final volume of 200 μl binding buffer (5% DMSO, 50 mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 10 μM unlabeled naloxone or U69,593. All reactions were performed in 96-well polypropylene plates for 1 hour at a temperature of about 25° C. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.) presoaked in 0.5% polyethylenimine (Sigma). Harvesting was performed using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by five filtration washes with 200 μl ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 1-2 hours. Fifty μl/well scintillation cocktail (Perkin Elmer, Shelton, Conn.) was added and plates were counted in a Packard Top-Count for 1 min/well.
- δ-Opioid Receptor Binding Assay δ-Opioid Receptor Binding Assay Procedures: δ-Opioid Receptor Binding Assay Procedures were conducted as follows. Radioligand dose-displacement assays used 0.3 nM [3H]-Naltrindole (Perkin Elmer, Shelton, Conn.; 33.0 Ci/mmole) with 5 μg membrane protein (Perkin Elmer, Shelton, Conn.) in a final volume of 500 μl binding buffer (5 mM MgCl2, 5% DMSO, 50 mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 25 μM unlabeled naloxone. All reactions were performed in 96-deep well polypropylene plates for 1 hour at a temperature of about 25° C. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.) presoaked in 0.5% polyethylenimine (Sigma). Harvesting was performed using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by five filtration washes with 500 μl ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 1-2 hours. Fifty μl/well scintillation cocktail (Perkin Elmer, Shelton, Conn.) was added and plates are counted in a Packard Top-Count for 1 min/well.δ-Opioid Receptor Binding Data: In certain embodiments, Compounds of the Invention exhibit a Ki (nM) for δ receptors of about 10,000 or more (which, for the purposes of this invention, is interpreted as having no binding to the δ receptors). Certain Compounds of the Invention exhibit a Ki (nM) of about 20,000 or less for δ receptors. In one embodiment, Compounds of the Invention exhibit a Ki (nM) of about 10,000 or less; or of about 9000 or less for δ receptors. In another embodiment, Compounds of the Invention exhibit a Ki (nM) of about 7500 or less; or of about 6500 or less; or of about 5000 or less; or of about 3000 or less; or of about 2500 or less for δ receptors. In another embodiment, Compounds of the Invention exhibit a Ki (nM) of about 1000 or less; or of about 500 or less; or of about 350 or less; or of about 250 or less; or of about 100 or less; or of about 10 or less for δ receptors.
- κ-Opioid Receptor Binding Assay κ-Opioid Receptor Binding Assay Procedures: Membranes from HEK-293 cells, CHO cells or U-2 OS cells expressing the recombinant human kappa opioid receptor (κ) were prepared by lysing cells in ice cold hypotonic buffer (2.5 mM MgCl2, 50 mM HEPES, pH 7.4) (10 mL/10 cm dish) followed by homogenization with a tissue grinder/Teflon pestle. Membranes from a cell line naturally expressing kappa opioid receptor can also be used. Membranes were collected by centrifugation at 30,000×g for 15 min at 4° C. and pellets were resuspended in hypotonic buffer to a final concentration of 1-3 mg/mL. Protein concentrations were determined using the BioRad protein assay reagent with bovine serum albumen as standard. Aliquots of κ receptor membranes were stored at −80° C.Radioligand dose displacement assays used 0.4 nM [3H]-U69,593 (GE Healthcare, Piscataway, N.J.; 40 Ci/mmole) with 15 μg membrane protein (recombinant opioid receptor expressed in HEK 293 cells; in-house prep) in a final volume of 200 μl binding buffer (5% DMSO, 50 mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 10 μM unlabeled naloxone or U69,593. All reactions were performed in 96-well polypropylene plates for 1 hour at a temperature of about 25° C. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.) presoaked in 0.5% polyethylenimine (Sigma). Harvesting was performed using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by five filtration washes with 200 μl ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 1-2 hours. Fifty μl/well scintillation cocktail (Perkin Elmer, Shelton, Conn.) was added and plates were counted in a Packard Top-Count for 1 min/well.
- Receptor Binding Assay κ-Opioid: Receptor Binding Assay Procedures: Membranes from HEK-293, CHO or U-2 OS cells expressing the recombinant human kappa opioid receptor (κ) were prepared by lysing cells in ice cold hypotonic buffer (2.5 mM MgCl2, 50 mM HEPES, pH 7.4) (10 mL/10 cm dish) followed by homogenization with a tissue grinder/Teflon pestle. Membranes from a cell line naturally expressing kappa opioid receptor can also be used. Membranes were collected by centrifugation at 30,000×g for 15 min at 4° C. and pellets were resuspended in hypotonic buffer to a final concentration of 1-3 mg/mL. Protein concentrations were determined using the BioRad protein assay reagent with bovine serum albumen as standard. Aliquots of κ receptor membranes were stored at −80° C.Radioligand dose displacement assays used 0.4 nM [3H]-U69,593 (GE Healthcare, Piscataway, N.J.; 40 Ci/mmole) with 15 μg membrane protein (recombinant κ opioid receptor expressed in HEK 293 cells; in-house prep) in a final volume of 200 μl binding buffer (5% DMSO, 50 mM Trizma base, pH 7.4). Non-specific binding was determined in the presence of 10 μM unlabeled naloxone or U69,593. All reactions were performed in 96-well polypropylene plates for 1 hour at a temperature of about 25° C. Binding reactions were terminated by rapid filtration onto 96-well Unifilter GF/C filter plates (Perkin Elmer, Shelton, Conn.) presoaked in 0.5% polyethylenimine (Sigma). Harvesting was performed using a 96-well tissue harvester (Perkin Elmer, Shelton, Conn.) followed by five filtration washes with 200 μl ice-cold binding buffer. Filter plates were subsequently dried at 50° C. for 1-2 hours. Fifty μl/well scintillation cocktail (Perkin Elmer, Shelton, Conn.) was added and plates were counted in a Packard Top-Count for 1 min/well.