CHEMBL3888264

In Vitro Mu-Opioid Receptor Functional Assay: [35S]GTPγS functional assays were conducted using freshly thawed membranes expressing human μ-receptors. Assay reactions were prepared by sequentially adding the following reagents to binding buffer (100 mM NaCl, 10 mM MgCl2, 20 mM HEPES, pH 7.4) on ice (final concentrations indicated): membrane protein (0.026 mg/mL), saponin (10 mg/mL), GDP (3 mM) and [35S]GTPγS (0.20 nM; NEN). The prepared membrane solution (190 μL/well) was transferred to 96-shallow well polypropylene plates containing 10 μL of 20× concentrated stock solutions of the agonist DAMGO ([D-Ala2, N-methyl-Phe4 Gly-o15]-enkephalin) prepared in dimethyl sulfoxide (DMSO). Plates were incubated for 30 min at about 25 °C. with shaking. Reactions were terminated by rapid filtration onto 96-well Unifilter GF/B filter plates (Packard, Meriden, Conn.) using a 96-well tissue harvester (Brandel, Gaithersburg, Md.) followed by three filtration washes with 200 μL of ice-cold wash buffer (10 mM NaH2PO4, 10 mM Na2HPO4, pH 7.4). Filter plates were subsequently dried at 50 °C. for 2-3 hr. BetaScint scintillation cocktail (Wallas, Turku, Finland) was added (50 μL/well) and plates were counted using a Packard Top-Count for 1 min/well.