CHEMBL5732313

M3 Binding Assay: Human M3 receptor membranes (15 μg/well) from Perkin Elmer are incubated with 0.52 nM Scopolamine Methyl Chloride, [N-methyl-3H] with or without test compounds, or a saturating concentration of Atropine (5 μM) for the determination of non-specific binding. The assay is carried out in 96-well polypropylene plates in a volume of 250 μl. The assay buffer used is 50 mM Tris-HCl, 154 mM NaCl (pH 7.4). The final assay concentration of DMSO is 0.5% (v/v). The plates are sealed and incubated for 2 h at room temperature on an orbital shaker (slow speed). Membranes are harvested onto 96-well unifilter GF/C filter plates pre-treated with 0.5% polyethyleneimine (v/v), using a filter manifold, washed four times with 200 μl of assay buffer. The plates are dried before addition of 50 μl of microscint-0, sealed then read in a Trilux Microbeta scintillation counter. IC50 values are determined from competition curves using a non-linear curve fitting program. Ki values are calculated from IC50 values by the Cheng and Prusoff equation.