| Assay Method Information | |
| | [3H]BRL 43694 Competition Binding (h-5HT3 Assay |
| Description: | [3H]BRL 43694 competition binding assay was performed under contract by Cerep Poitiers, France following the methods described in Hope, A. G et al., Characterization of a human 5-hydroxytryptamine3 receptor type A (h5-HT3R-AS) subunit stably expressed in HEK 293 cells, Brit. J. Pharmacol., (1996) 118: 1237-1245.In brief, Chinese Hamster Ovary (CHO) cells stably expressing human 5-HT3 serotonin receptors, grown to confluence in 175 cm2 flasks. Following aspiration of the culture medium, cells were harvested by mechanical agitation in ice cold PBS containing (in mM): (150 NaCl, 8 K2HPO4, 2 KH2PO4, pH 7.4, 37° C.), centrifuged at 4,000 g for 10 min and subsequently stored as a cell pellet at −80 C. When required, the pellet was thawed and resuspended in ice cold homogenization buffer (Tris 50 mM, EGTA 5.0 mM, phenylmethylsulphonylfluoride 0.1 mM, pH 7.6) and homogenized. The homogenate was centrifuged at 48,000 g for 10 minutes at 40° C. The resulting pellet was resuspended in ice cold binding buffer comprising (in mM): NaCl 140, KCl 2.8, CaCl2 1.0; MgCl2, 2.0; HEPES 10 (pH 7.4) and centrifuged as above. The pellet was resuspended in ice cold binding buffer and the protein concentration was determined by the method of Lowry et al., Protein measurement with the Folin phenol reagent, J. Biol. Chem., (1953) 193, 265-275). The membrane homogenate was adjusted to a protein concentration of approximately 600 mg/mL in binding buffer. Assay tubes were loaded with equal volumes of binding buffer containing [3H]BRL 43694 and test compound and 0.5 mL of membrane homogenate in a total reaction volume of 1 ml. Binding was initiated by the addition of the membrane homogenate and allowed to proceed for 120 min. at room temperature. Bound and free radioligand were separated by the addition of 3 ml of ice-cold binding buffer and immediate vacuum filtration through pre-soaked (0.1% (v/v) polyethyleneimine) Whatman GF/B filters. Filters were washed with a further 2×3 mL applications of binding buffer and counted for radioactivity using a scintillation counter.The results were expressed as a percent inhibition of control specific binding obtained in the presence of the test compounds where Inhibition (%)=100−[(measured specific binding/control specific binding)×100]. |
| Affinity data for this assay | |
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