CHEMBL3706294

Radioligand Binding Assay: The relative affinity of the various compounds for the human 5-HT3 receptor was measured in a radioligand binding assay, using a scintillation proximity assay (SPA) format. Test compounds were dissolved to 10 mM in 100% DMSO, then serially diluted at 10x assay concentrations in 100% DMSO in 96-well polypropylene plates and further diluted to 4x assay concentrations with the assay buffer. Samples were incubated in 50 mM Tris-HCl, pH 7.5, 3 mM MgCl2, 1 mM EDTA and 10% DMSO with 10 nM [9-methyl-3H]BRL-43694 (Perkin Elmer), 3 ug of human 5-HT3 receptor membranes (Perkin Elmer) and 0.5 mg/mL SPA beads (WGA PVT, Amersham Biosciences) in a final volume of 0.2 mL. Binding reactions were set up in wells of PicoPlates-96 (Perkin Elmer) by adding consecutively 50 uL of each competing compound or buffer, SPA beads, the radioligand and 5-HT3 receptor membranes. After an overnight incubation at room temperature on a Nutator mixer, plates were centrifuged for 15 min at 1,500 rpm.