- ChEMBL_1501892 (CHEMBL3588150) Displacement of [3H]EMPA from human OX2 receptor expressed in human PFSK-1 cells
- ChEMBL_1507900 (CHEMBL3598993) Displacement of [3H]EMPA from human orexin-2 receptor expressed in HEK293 cells after 60 mins by scintillation counting analysis
- Biological Assay The in vitro affinity of the compounds for the human orexin-1 and orexin-2 receptors was determined by competitive radioligand binding using [3H]SB SB674042 (1-(5-(2-fluoro-phenyl)-2-methyl-thiazol-4-yl)-1-((S)-2-(5-phenyl-(1,3,4)oxadiazol-2-ylmethyl)-pyrrolidin-1-yl)-methanone) (Langmead et al., British Journal of Pharmacology 2004, 141:340-346) and [3H]EMPA (N-ethyl-2[(6-methoxy-pyridin-3-yl)-(toluene-2-sulfonyl)-amino]-N-pyridin-3-ylmethyl acetamide) (Malherbe et al., British Journal of Pharmacology, 2009, 156(8), 1326-1341), respectively. The in vitro functional antagonism of the compounds on the human orexin-1 and orexin-2 receptors was determined using fluorometric imaging plate reader (FLIPR) based calcium assays.
- Radioligand Binding Assay HEK293 stably expressing human orexin 2 receptor (Genebank accession number NM 001526) were grown to confluency in DMEM (Hyclone, cat # SH30022), 10% FBS, 1x Pen/Strep, 1x NaPyruvate, 10 mM HEPES, 600 ug/ml G418 media on 150 cm2 tissue culture plates, washed with 5 mM EDTA in PBS (HyClone Dulbecco's Phosphate Buffered Saline 1x with Calcium and Magnesium, Cat # SH30264.01, hereafter referred to simply as PBS) and scraped into 50 ml tubes. After centrifugation (2Kx G, 5 min at 4x C.), the supernatant was aspirated and the pellets frozen and stored at -80 C. Cells were resuspended in PBS in the presence of 1 tablet of protease inhibitor cocktail (Roche, Cat. #11836145001) per 50 mL. Each cell pellet from a 15 cm plate was resuspended in 10 mL, stored on ice, and homogenized for 45 sec just prior to addition to the reactions. Competition binding experiments in 96 well polypropylene plates were performed using [3H]-EMPA (Moraveck Corporation, specific activity=29.6 Ci/mmol).
- Radioligand Binding Assay HEK293 stably expressing human orexin 2 receptor (Genebank accession number NM001526) were grown to confluency in DMEM (Hyclone, cat #SH30022), 10% FBS, 1x Pen/Strep, 1x NaPyruvate, 10 mM HEPES, 600 ug/ml G418 media on 150 cm2 tissue culture plates, washed with 5 mM EDTA in PBS (HyClone Dulbecco's Phosphate Buffered Saline 1x with Calcium and Magnesium, Cat # SH30264.01, hereafter referred to simply as PBS) and scraped into 50 ml tubes. After centrifugation (2K xG, 5 min at 40 C.), the supernatant was aspirated and the pellets frozen and stored at -80 C. Cells were resuspended in PBS in the presence of 1 tablet of protease inhibitor cocktail (Roche, Cat. #11836145001) per 50 mL. Each cell pellet from a 15 cm plate was resuspended in 10 mL, stored on ice, and homogenized for 45 sec just prior to addition to the reactions. Competition binding experiments in 96 well polypropylene plates were performed using [3H]-EMPA (Moraveck Corporation, specific activity=29.6 Ci/mmol).
- Radioligand Binding Assay HEK293 stably expressing human orexin 2 receptor (Genebank accession numberNM_001526) were grown to confluency in DMEM (Hyclone, cat # SH30022) , 10%FBS, IX Pen/Strep, IX NaPyruvate, 10 mM HEPES, 600 ug/ml G418 media on 150 cm2 tissue culture plates, washed with 5 mM EDTA in PBS (HyClone Dulbecco's Phoshpate Buffered Saline IX with Calcium and Magnesium, Cat # SH30264.01, hereafter referred to simply as PBS) and scraped into 50 ml tubes. After centrifugation (2K xG, 5 min at 4 °C), the supernatant was aspirated and the pellets frozen and stored at -80 °C. Cells were resuspended in PBS in the presence of 1 tablet of protease inhibitor cocktail (Roche, Cat. #11836145001) per 50 mL. Each cell pellet from a 15 cm plate was resuspended in 10 mL, stored on ice, and homogenized for 45 sec just prior to addition to the reactions. Competition binding experiments in 96 well polypropylene plates were performed using [3H]-EMPA (Moraveck Corporation, specific activity = 29.6 Ci/mmol).
- Human Orexin 2 Receptor Radioligand Binding Assay HEK293 stably expressing human orexin 2 receptor (Genebank accession number NM_001526) were grown to confluency in DMEM (Hyclone, cat #SH30022), 10% FBS, 1× Pen/Strep, 1× NaPyruvate, 10 mM HEPES, 600 ug/ml G418 media on 150 cm2 tissue culture plates, washed with 5 mM EDTA in PBS (HyClone Dulbecco's Phosphate Buffered Saline 1× with Calcium and Magnesium, Cat #SH30264.01, hereafter referred to simply as PBS) and scraped into 50 ml tubes. After centrifugation (2K×G, 5 min at 40° C.), the supernatant was aspirated and the pellets frozen and stored at −800° C. Cells were resuspended in PBS in the presence of 1 tablet of protease inhibitor cocktail (Roche, Cat. #11836145001) per 50 mL. Each cell pellet from a 15 cm plate was resuspended in 10 mL, stored on ice, and homogenized for 45 sec just prior to addition to the reactions. Competition binding experiments in 96 well polypropylene plates were performed using [3H]-EMPA (Moraveck Corporation, specific activity=29.6 Ci/mmol), diluted to a 5 nM concentration in PBS (2 nM final concentration). Compounds were solubilized in 100% DMSO (Acros Organics, Cat. #61042-1000) and tested over a range of 7 concentration (from 0.1 nM to 10 μM). The final concentration of DMSO in the reactions is equal to or less than 0.1%. Total and nonspecific binding was determined in the absence and presence of 10 μM almorexant. The total volume of each reaction is 200 μL (20 μL of diluted compounds, 80 μL of [3H]-EMPA diluted in PBS and 100 μL of the cell suspension). Reactions were run for 60 min at room temperature and terminated by filtration through GF/C filter plates (PerkinElmer, Cat. #6005174) presoaked in 0.3% polyethylenimine using the cell harvester (PerkinElmer Filtermate). The plates were washed 3 times by aspirating 30 ml PBS through the plates. Plates were dried in 55° C. oven for 60 min, scintillation fluid was added, and the radioactivity was counted on a Topcount (Packard).
- Radioligand Binding Assay HEK293 stably expressing human orexin 2 receptor (Genebank accession number NM_001526) were grown to confluency in DMEM (Hyclone, cat # SH30022), 10% FBS, 1× Pen/Strep, 1× NaPyruvate, 10 mM HEPES, 600 g/ml G418 media on 150 cm2 tissue culture plates, washed with 5 mM EDTA in PBS (HyClone Dulbecco's Phosphate Buffered Saline 1× with Calcium and Magnesium, Cat # SH30264.01, hereafter referred to simply as PBS) and scraped into 50 ml tubes. After centrifugation (2K ×G, 5 min at 40° C.), the supernatant was aspirated and the pellets frozen and stored at 800° C. Cells were resuspended in PBS in the presence of 1 tablet of protease inhibitor cocktail (Roche, Cat. #11836145001) per 50 mL. Each cell pellet from a 15 cm plate was resuspended in 10 mL, stored on ice, and homogenized for 45 sec just prior to addition to the reactions. Competition binding experiments in 96 well polypropylene plates were performed using [3H]-EMPA (Moraveck Corporation, specific activity=29.6 Ci/mmol), diluted to a 5 nM concentration in PBS (2 nM final concentration). Compounds were solubilized in 100% DMSO (Acros Organics, Cat. #61042-1000) and tested over a range of 7 concentration (from 0.1 nM to 10 μM). The final concentration of DMSO in the reactions is equal to or less than 0.1%. Total and nonspecific binding was determined in the absence and presence of 10 M almorexant. The total volume of each reaction is 200 μL (20 μL of diluted compounds, 80 μL of [3H]-EMPA diluted in PBS and 100 μL of the cell suspension). Reactions were run for 60 min at room temperature and terminated by filtration through GF/C filter plates (PerkinElmer, Cat. #6005174) presoaked in 0.3% polyethylenimine using the cell harvester (PerkinElmer Filtermate). The plates were washed 3 times by aspirating 30 ml PBS through the plates. Plates were dried in 55° C. oven for 60 min, scintillation fluid was added, and the radioactivity was counted on a Topcount (Packard).
- Radioligand Binding Assay HEK293 stably expressing human orexin 2 receptor (Genebank accession number NM_001526) were grown to confluency in DMEM (Hyclone, cat # SH30022), 10% FBS, 1× Pen/Strep, 1× NaPyruvate, 10 mM HEPES, 600 ug/ml G418 media on 150 cm2 tissue culture plates, washed with 5 mM EDTA in PBS (HyClone Dulbecco's Phosphate Buffered Saline 1× with Calcium and Magnesium, Cat # SH30264.01, hereafter referred to simply as PBS) and scraped into 50 ml tubes. After centrifugation (2K×G, 5 min at 4° C.), the supernatant was aspirated and the pellets frozen and stored at −80° C. Cells were resuspended in PBS in the presence of 1 tablet of protease inhibitor cocktail (Roche, Cat. #11836145001) per 50 mL. Each cell pellet from a 15 cm plate was resuspended in 10 mL, stored on ice, and homogenized for 45 sec just prior to addition to the reactions. Competition binding experiments in 96 well polypropylene plates were performed using [3H]-EMPA (Moraveck Corporation, specific activity=29.6 Ci/mmol), diluted to a 5 nM concentration in PBS (2 nM final concentration). Compounds were solubilized in 100% DMSO (Acros Organics, Cat. #61042-1000) and tested over a range of 7 concentration (from 0.1 nM to 10 μM). The final concentration of DMSO in the reactions is equal to or less than 0.1%. Total and nonspecific binding was determined in the absence and presence of 10 μM almorexant. The total volume of each reaction is 200 μL (20 μL of diluted compounds, 80 μL of [3H]-EMPA diluted in PBS and 100 μL of the cell suspension). Reactions were run for 60 min at room temperature and terminated by filtration through GF/C filter plates (PerkinElmer, Cat. #6005174) presoaked in 0.3% polyethylenimine using the cell harvester (PerkinElmer Filtermate). The plates were washed 3 times by aspirating 30 ml PBS through the plates. Plates were dried in 55° C. oven for 60 min, scintillation fluid was added, and the radioactivity was counted on a Topcount (Packard).
- Radioligand Binding Assay HEK293 stably expressing human orexin 2 receptor (Genebank accession number NM_001526) were grown to confluency in DMEM (Hyclone, cat #SH30022), 10% FBS, 1x Pen/Strep, 1x NaPyruvate, 10 mM HEPES, 600 ug/ml G418 media on 150 cm2 tissue culture plates, washed with 5 mM EDTA in PBS (HyClone Dulbecco's Phosphate Buffered Saline 1x with Calcium and Magnesium, Cat #SH30264.01, hereafter referred to simply as PBS) and scraped into 50 ml tubes. After centrifugation (2KxG, 5 min at 40° C.), the supernatant was aspirated and the pellets frozen and stored at -800° C. Cells were resuspended in PBS in the presence of 1 tablet of protease inhibitor cocktail (Roche, Cat. #11836145001) per 50 mL. Each cell pellet from a 15 cm plate was resuspended in 10 mL, stored on ice, and homogenized for 45 sec just prior to addition to the reactions. Competition binding experiments in 96 well polypropylene plates were performed using [3H]-EMPA (Moraveck Corporation, specific activity=29.6 Ci/mmol), diluted to a 5 nM concentration in PBS (2 nM final concentration). Compounds were solubilized in 100% DMSO (Acros Organics, Cat. #61042-1000) and tested over a range of 7 concentration (from 0.1 nM to 10 uM). The final concentration of DMSO in the reactions is equal to or less than 0.1%. Total and nonspecific binding was determined in the absence and presence of 10 uM almorexant. The total volume of each reaction is 200 uL (20 uL of diluted compounds, 80 uL of [3H]-EMPA diluted in PBS and 100 uL of the cell suspension). Reactions were run for 60 min at room temperature and terminated by filtration through GF/C filter plates (PerkinElmer, Cat. #6005174) presoaked in 0.3% polyethylenimine using the cell harvester (PerkinElmer Filtermate). The plates were washed 3 times by aspirating 30 ml PBS through the plates. Plates were dried in 55° C. oven for 60 min, scintillation fluid was added, and the radioactivity was counted on a Topcount (Packard).
- Receptor Radioligand Binding Assay HEK293 stably expressing human orexin 2 receptor (Genebank accession number NM_001526) were grown to confluency in DMEM (Hyclone, cat # SH30022), 10% FBS, 1× Pen/Strep, 1× NaPyruvate, 10 mM HEPES, 600 μg/ml G418 media on 150 cm2 tissue culture plates, washed with 5 mM EDTA in PBS (HyClone Dulbecco's Phosphate Buffered Saline 1× with Calcium and Magnesium, Cat # SH30264.01, hereafter referred to simply as PBS) and scraped into 50 ml tubes. After centrifugation (2K×G, 5 min at 4° C.), the supernatant was aspirated and the pellets frozen and stored at −80° C. Cells were resuspended in PBS in the presence of 1 tablet of protease inhibitor cocktail (Roche, Cat. #11836145001) per 50 mL. Each cell pellet from a 15 cm plate was resuspended in 10 mL, stored on ice, and homogenized for 45 sec just prior to addition to the reactions. Competition binding experiments in 96 well polypropylene plates were performed using [3H]-EMPA (Moraveck Corporation, specific activity=29.6 Ci/mmol), diluted to a 5 nM concentration in PBS (2 nM final concentration). Compounds were solubilized in 100% DMSO (Acros Organics, Cat. #61042-1000) and tested over a range of 7 concentration (from 0.1 nM to 10 μM). The final concentration of DMSO in the reactions is equal to or less than 0.1%. Total and nonspecific binding was determined in the absence and presence of 10 μM almorexant. The total volume of each reaction is 200 μL (20 μL of diluted compounds, 80 μL of [3H]-EMPA diluted in PBS and 100 μL of the cell suspension). Reactions were run for 60 min at room temperature and terminated by filtration through GF/C filter plates (PerkinElmer, Cat. #6005174) presoaked in 0.3% polyethylenimine using the cell harvester (PerkinElmer Filtermate). The plates were washed 3 times by aspirating 30 ml PBS through the plates. Plates were dried in 55° C. oven for 60 min, scintillation fluid was added, and the radioactivity was counted on a Topcount (Packard).
- Receptor Radioligand Binding Assay HEK293 stably expressing human orexin 2 receptor (Genebank accession number NM_001526) were grown to confluency in DMEM (Hyclone, cat #SH30022), 10% FBS, 1×Pen/Strep, 1× NaPyruvate, 10 mM HEPES, 600 ug/ml G418 media on 150 cm2 tissue culture plates, washed with 5 mM EDTA in PBS (HyClone Dulbecco's Phosphate Buffered Saline 1× with Calcium and Magnesium, Cat #SH30264.01, hereafter referred to simply as PBS) and scraped into 50 ml tubes. After centrifugation (2K×G, 5 min at 4° C.), the supernatant was aspirated and the pellets frozen and stored at −80° C. Cells were resuspended in PBS in the presence of 1 tablet of protease inhibitor cocktail (Roche, Cat. #11836145001) per 50 mL. Each cell pellet from a 15 cm plate was resuspended in 10 mL, stored on ice, and homogenized for 45 sec just prior to addition to the reactions. Competition binding experiments in 96 well polypropylene plates were performed using [3H]-EMPA (Moraveck Corporation, specific activity=29.6 Ci/mmol), diluted to a 5 nM concentration in PBS (2 nM final concentration). Compounds were solubilized in 100% DMSO (Acros Organics, Cat. #61042-1000) and tested over a range of 7 concentration (from 0.1 nM to 10 μM). The final concentration of DMSO in the reactions is equal to or less than 0.1%. Total and nonspecific binding was determined in the absence and presence of 10 μM almorexant. The total volume of each reaction is 200 μL (20 μL of diluted compounds, 80 μL of [3H]-EMPA diluted in PBS and 100 μL of the cell suspension). Reactions were run for 60 min at room temperature and terminated by filtration through GF/C filter plates (PerkinElmer, Cat. #6005174) presoaked in 0.3% polyethylenimine using the cell harvester (PerkinElmer Filtermate). The plates were washed 3 times by aspirating 30 ml PBS through the plates. Plates were dried in 55° C. oven for 60 min, scintillation fluid was added, and the radioactivity was counted on a Topcount (Packard).
- Receptor Radioligand Binding Assay Human Orexin 2 Receptor:HEK293 stably expressing human orexin 2 receptor (Genebank accession number NM_001526) were grown to confluency in DMEM (Hyclone, cat # SH30022), 10% FBS, 1× Pen/Strep, 1× NaPyruvate, 10 mM HEPES, 600 ug/ml G418 media on 150 cm2 tissue culture plates, washed with 5 mM EDTA in PBS (HyClone Dulbecco's Phosphate Buffered Saline 1× with Calcium and Magnesium, Cat # SH30264.01, hereafter referred to simply as PBS) and scraped into 50 ml tubes. After centrifugation (2K×G, 5 min at 4° C.), the supernatant was aspirated and the pellets frozen and stored at −80° C. Cells were resuspended in PBS in the presence of 1 tablet of protease inhibitor cocktail (Roche, Cat. #11836145001) per 50 mL. Each cell pellet from a 15 cm plate was resuspended in 10 mL, stored on ice, and homogenized for 45 sec just prior to addition to the reactions. Competition binding experiments in 96 well polypropylene plates were performed using [3H]-EMPA (Moraveck Corporation, specific activity=29.6 Ci/mmol), diluted to a 5 nM concentration in PBS (2 nM final concentration). Compounds were solubilized in 100% DMSO (Acros Organics, Cat. #61042-1000) and tested over a range of 7 concentration (from 0.1 nM to 10 μM). The final concentration of DMSO in the reactions is equal to or less than 0.1%. Total and nonspecific binding was determined in the absence and presence of 10 μM almorexant. The total volume of each reaction is 200 μL (20 μL of diluted compounds, 80 μL of [3H]-EMPA diluted in PBS and 100 μL of the cell suspension). Reactions were run for 60 min at room temperature and terminated by filtration through GF/C filter plates (PerkinElmer, Cat. #6005174) presoaked in 0.3% polyethylenimine using the cell harvester (PerkinElmer Filtermate). The plates were washed 3 times by aspirating 30 ml PBS through the plates. Plates were dried in 55° C. oven for 60 min, scintillation fluid was added, and the radioactivity was counted on a Topcount (Packard).
- Human Orexin 2 Receptor Radioligand Binding Studies HEK293 stably expressing human orexin-2 receptor (Genebank accession number NM_001526) were grown to confluency in DMEM/F12 (Gibco, Cat #11039), in DMEM, 10% FBS, 1× Pen/Strep, 1× NaPyruvate, 1×HEPES, 600 ug/ml G418 media on 150 cm2 tissue culture plates, washed with 5 mM EDTA in PBS (HyClone Dulbecco's Phosphate Buffered Saline 1× with Calcium and Magnesium, Cat #SH30264.01, hereafter referred to simply as PBS) and scraped into 50 ml tubes. After centrifugation (2K×G, 10 min at 4° C.), the supernatant was aspirated and the pellets frozen and stored at −80° C. Cells were resuspended in PBS in the presence of 1 tablet of protease inhibitor cocktail (Roche, Cat. #11836145001) per 50 mL. Each cell pellet from a 15 cm plate was resuspended in 10 mL, stored on ice, and vortexed for 45 sec just prior to addition to the reactions. Competition binding experiments in 96 well polypropylene plates were performed using [3H]-EMPA (Moravek Corporation, specific activity=27 Ci/mmol), diluted to a 20 nM concentration in PBS (5 nM final concentration). Compounds were solubilized in 100% DMSO (Acros Organics, Cat. #61042-1000) and tested over a range of 7 concentrations (from 0.1 nM to 10 μM). The final concentration of DMSO in the reactions is equal to or less than 0.1%. Total and nonspecific binding was determined in the absence and presence of 10 μM (N-[2-(3,4-dimethoxyphenyl)ethyl]-N-methylnaphthalene-1-carboxamide, CAS Registry #1089563-88-1). The total volume of each reaction is 200 μL (20 μL of diluted compounds, 80 μL of [3H]-EMPA diluted in PBS and 100 μL of the cell suspension). Reactions were run for 60 min at room temperature and terminated by filtration through GF/C filter plates (PerkinElmer, Cat. #6005174) presoaked in 0.3% polyethylenimine using the cell harvester (PerkinElmer Filtermate). The plates were washed 3 times by aspirating 30 ml PBS through the plates. Plates were dried in 55° C. oven for 60 min, scintillation fluid was added, and the radioactivity was counted on a Topcount (Packard).
- Receptor Radioligand Binding Assay HEK293 stably expressing human orexin-2 receptor (Genebank accession number NM_001526) were grown to confluency in DMEM/F12 (Gibco, Cat #11039), in DMEM, 10% FBS, 1× Pen/Strep, 1× NaPyruvate, 1×HEPES, 600 ug/ml G418 media on 150 cm2 tissue culture plates, washed with 5 mM EDTA in PBS (HyClone Dulbecco's Phosphate Buffered Saline 1× with Calcium and Magnesium, Cat # SH30264.01, hereafter referred to simply as PBS) and scraped into 50 ml tubes. After centrifugation (2K×G, 10 min at 4° C.), the supernatant was aspirated and the pellets frozen and stored at −80° C. Cells were resuspended in PBS in the presence of 1 tablet of protease inhibitor cocktail (Roche, Cat. #11836145001) per 50 mL. Each cell pellet from a 15 cm plate was resuspended in 10 mL, stored on ice, and vortexed for 45 sec just prior to addition to the reactions. Competition binding experiments in 96 well polypropylene plates were performed using [3H]-EMPA (Moravek Corporation, specific activity=27 Ci/mmol), diluted to a 20 nM concentration in PBS (5 nM final concentration). Compounds were solubilized in 100% DMSO (Acros Organics, Cat. #61042-1000) and tested over a range of 7 concentrations (from 0.1 nM to 10 μM). The final concentration of DMSO in the reactions is equal to or less than 0.1%. Total and nonspecific binding was determined in the absence and presence of 10 μM (N-[2-(3,4-dimethoxyphenyl)ethyl]-N-methylnaphthalene-1-carboxamide, CAS Registry #1089563-88-1). The total volume of each reaction is 200 μL (20 μL of diluted compounds, 80 μL of [3H]-EMPA diluted in PBS and 100 μL of the cell suspension). Reactions were run for 60 min at room temperature and terminated by filtration through GF/C filter plates (PerkinElmer, Cat. #6005174) presoaked in 0.3% polyethylenimine using the cell harvester (PerkinElmer Filtermate). The plates were washed 3 times by aspirating 30 ml PBS through the plates. Plates were dried in 55° C. oven for 60 min, scintillation fluid was added, and the radioactivity was counted on a Topcount (Packard).
- Human Orexin 2 Receptor Radioligand Binding Studies HEK293 stably expressing human orexin-2 receptor (Genebank accession number NM_001526) were grown to confluency in DMEM/F12 (Gibco, Cat #11039), in DMEM, 10% FBS, 1× Pen/Strep, 1× NaPyruvate, 1× HEPES, 600 ug/ml G418 media on 150 cm2 tissue culture plates, washed with 5 mM EDTA in PBS (HyClone Dulbecco's Phoshpate Buffered Saline 1× with Calcium and Magnesium, Cat # SH30264.01, hereafter referred to simply as PBS) and scraped into 50 ml tubes. After centrifugation (2K×G, 10 min at 4° C.), the supernatant was aspirated and the pellets frozen and stored at −80° C. Cells were resuspended in PBS in the presence of 1 tablet of protease inhibitor cocktail (Roche, Cat. #11836145001) per 50 mL. Each cell pellet from a 15 cm plate was resuspended in 10 mL, stored on ice, and vortexed for 45 sec just prior to addition to the reactions. Competition binding experiments in 96 well polypropylene plates were performed using [3H]-EMPA (Moravek Corporation, specific activity=27 Ci/mmol), diluted to a 20 nM concentration in PBS (5 nM final concentration). Compounds were solubilized in 100% DMSO (Acros Organics, Cat. #61042-1000) and tested over a range of 7 concentrations (from 0.1 nM to 10 μM). The final concentration of DMSO in the reactions is equal to or less than 0.1%. Total and nonspecific binding was determined in the absence and presence of 10 μM (N-[2-(3,4-dimethoxyphenyl)ethyl]-N-methylnaphthalene-1-carboxamide, CAS Registry #1089563-88-1). The total volume of each reaction is 200 μL (20 μL of diluted compounds, 80 μL of [3H]-EMPA diluted in PBS and 100 μL of the cell suspension). Reactions were run for 60 min at room temperature and terminated by filtration through GF/C filter plates (PerkinElmer, Cat. #6005174) presoaked in 0.3% polyethylenimine using the cell harvester (Perkin Elmer Filtermate). The plates were washed 3 times by aspirating 30 ml PBS through the plates. Plates were dried in 55° C. oven for 60 min, scintillation fluid was added, and the radioactivity was counted on a Topcount (Packard). IC50 values (i.e. concentration of unlabelled compound required to compete for 50% of specific binding to the radioligand) were calculated using the GraphPad Prism software (GraphPad Prism Software Inc., San Diego, Calif.) with a fit to a sigmoidal dose-response curve. Apparent Ki values were calculated as Ki=IC50/(1+C/Kd), where C is concentration of radioligand and Kd=2 nM.
- Human Orexin 2 Receptor Radioligand Binding Studies HEK293 stably expressing human orexin-2 receptor (Genebank accession number NM_001526) were grown to confluency in DMEM/F12 (Gibco, Cat #11039), in DMEM, 10% FBS, 1× Pen/Strep, 1× NaPyruvate, 1×HEPES, 600 ug/ml G418 media on 150 cm2 tissue culture plates, washed with 5 mM EDTA in PBS (HyClone Dulbecco's Phosphate Buffered Saline 1× with Calcium and Magnesium, Cat #SH30264.01, hereafter referred to simply as PBS) and scraped into 50 ml tubes. After centrifugation (2K xG, 10 min at 4° C.), the supernatant was aspirated and the pellets frozen and stored at −80° C. Cells were resuspended in PBS in the presence of 1 tablet of protease inhibitor cocktail (Roche, Cat. #11836145001) per 50 mL. Each cell pellet from a 15 cm plate was resuspended in 10 mL, stored on ice, and vortexed for 45 sec just prior to addition to the reactions. Competition binding experiments in 96 well polypropylene plates were performed using [3H]-EMPA (Moravek Corporation, specific activity=27 Ci/mmol), diluted to a 20 nM concentration in PBS (5 nM final concentration). Compounds were solubilized in 100% DMSO (Acros Organics, Cat. #61042-1000) and tested over a range of 7 concentrations (from 0.1 nM to 10 μM). The final concentration of DMSO in the reactions is equal to or less than 0.1%. Total and nonspecific binding was determined in the absence and presence of 10 μM (N-[2-(3,4-dimethoxyphenyl)ethyl]-N-methylnaphthalene-1-carboxamide, CAS Registry #1089563-88-1). The total volume of each reaction is 200 μL (20 μL of diluted compounds, 80 μL of [3H]-EMPA diluted in PBS and 100 μL of the cell suspension). Reactions were run for 60 min at room temperature and terminated by filtration through GF/C filter plates (PerkinElmer, Cat. #6005174) presoaked in 0.3% polyethylenimine using the cell harvester (PerkinElmer Filtermate). The plates were washed 3 times by aspirating 30 ml PBS through the plates. Plates were dried in 55° C. oven for 60 min, scintillation fluid was added, and the radioactivity was counted on a Topcount (Packard). IC50 values (i.e. concentration of unlabelled compound required to compete for 50% of specific binding to the radioligand) were calculated using the GraphPad Prism software (GraphPad Prism Software Inc., San Diego, Calif.) with a fit to a sigmoidal dose-response curve. Apparent Ki values were calculated as Ki=IC50/(1+C/Kd), where C is concentration of radioligand and Kd=2 nM.
- Rat and Human Orexin 1 Receptor Radioligand Binding Studies Human Embryonic Kidney 293 cells (HEK293) stably expressing rat orexin 1 receptor (Genebank accession number NM_001525) or Chinese ovary cells (CHO) stably expressing human orexin 1 receptor (Genebank accession number NM_001526) were grown to confluency in DMEM (Hyclone, cat #SH30022), 10% FBS, 1× Pen/Strep, 1× sodium pyruvate, 10 mM HEPES, 600 μg/mL G418 and DMEM/F12 (Gibco, Cat #11039), 10% FBS, 1×Pen/Strep, 600 μg/mL G418 media, respectively on 150 cm2 tissue culture plates, washed with 5 mM EDTA in PBS (HyClone Dulbecco's Phosphate Buffered Saline 1× with Calcium and Magnesium, Cat #SH30264.01, hereafter referred to simply as PBS) and scraped into 50 ml tubes. After centrifugation (2K×G, 5 min at 4° C.), the supernatant was aspirated and the pellets frozen and stored at −80° C. Cells were resuspended in PBS in the presence of 1 tablet of protease inhibitor cocktail (Roche, Cat. #11836145001) per 50 mL. Each cell pellet from a 15 cm plate was resuspended in 10 mL, stored on ice, and homogenized for 45 sec prior to addition to the reactions. Competition binding experiments in 96 well polypropylene plates were performed using [3H]-(1-(5-(2-fluoro-phenyl)-2-methyl-thiazol-4-yl)-1-((S)-2-(5-phenyl-(1,3,4)oxadiazol-2-ylmethyl)-pyrrolidin-1-yl)-methanone) (Moraveck Corporation, specific activity=35.3 Ci/mmol), diluted to a 10 nM concentration in PBS (4 nM final). Compounds were solubilized in 100% DMSO (Acros Organics, Cat. #61042-1000) and tested over a range of 7 concentrations (from 0.1 nM to 10 μM). The final concentration of DMSO in the reactions is equal to or less than 0.1%. Total and nonspecific binding was determined in the absence and presence of 10 μM almorexant. The total volume of each reaction is 200 μL (20 μL of diluted compounds, 80 μL of [3H]-(1-(5-(2-fluoro-phenyl)-2-methyl-thiazol-4-yl)-1-((S)-2-(5-phenyl-(1,3,4)oxadiazol-2-ylmethyl)-pyrrolidin-1-yl)-methanone) diluted in PBS and 100 μL of the cell suspension). Reactions were run for 60 min at room temperature and terminated by filtration through GF/C filter plates (PerkinElmer, Cat. #6005174) presoaked in 0.3% polyethylenimine using the cell harvester (PerkinElmer Filtermate). The plates were washed 3 times by aspirating 30 ml PBS through the plates. Plates were dried in 55° C. oven for 60 min, scintillation fluid was added, and the radioactivity was counted on a Topcount (Packard).IC50 values (i.e. concentration of unlabelled compound required to compete for 50% of specific binding to the radioligand) was calculated using the GraphPad Prism software (GraphPad Prism Software Inc., San Diego, Calif.) with a fit to a sigmoidal dose-response curve. Apparent Ki values were calculated as Ki=IC50/(1+C/Kd), where C is concentration of radioligand and Kd=4 nM for rat orexin 1 receptor and 6 nM for human orexin 1 receptor.Human Orexin 2 Receptor Radioligand Binding StudiesHEK293 stably expressing human orexin 2 receptor (Genebank accession number NM_001526) were grown to confluency in DMEM (Hyclone, cat #SH30022), 10% FBS, 1×Pen/Strep, 1× NaPyruvate, 10 mM HEPES, 600 ug/ml G418 media on 150 cm2 tissue culture plates, washed with 5 mM EDTA in PBS (HyClone Dulbecco's Phosphate Buffered Saline 1× with Calcium and Magnesium, Cat #SH30264.01, hereafter referred to simply as PBS) and scraped into 50 ml tubes. After centrifugation (2K×G, 5 min at 4° C.), the supernatant was aspirated and the pellets frozen and stored at 80° C. Cells were resuspended in PBS in the presence of 1 tablet of protease inhibitor cocktail (Roche, Cat. #11836145001) per 50 mL. Each cell pellet from a 15 cm plate was resuspended in 10 mL, stored on ice, and homogenized for 45 sec just prior to addition to the reactions. Competition binding experiments in 96 well polypropylene plates were performed using [3]-EMPA (Moraveck Corporation, specific activity=29.6 Ci/mmol), diluted to a 5 nM concentration in PBS (2 nM final concentration).