CHEMBL5731335

Radioligand Competition Binding Assay: The binding affinities of certain compounds of the present invention were evaluated using radioligand binding assays in membranes prepared from CHO-K1 cells expressing recombinant human kappa (KOR) or mu (MOR) opioid receptors.Competition binding experiments were conducted by incubating membrane protein to equilibrium in triplicate in the presence of a fixed concentration of radioligand and increasing concentrations of test compound for evaluation of binding to KOR or single concentration (10 μM) of test compound for evaluation of binding to MOR in 101 μL final volume. The radioligands used were specific for each receptor type, and the assay conditions are described in Table 1. Following incubations, the membranes were rapidly filtered through GF/B filter plate (presoaked with 0.5% polyethyleneimine), washed five times with cold 50 mM Tris-HCl, pH 7.5, and the bound radioactivity was then measured by liquid scintillation counting. Non-specific binding was measured in the presence of excess ligand; this value was subtracted from the total binding to yield the specific binding at each test concentration.