CHEMBL3888041

GTPyS binding assay: Test compound and/or vehicle was preincubated with the cell membranes and 3 uM GDP in modified HEPES buffer (pH 7.4) for 20 minutes, followed by addition of SPA beads for another 60 minutes at 30° C. The reaction is initiated by 0.3 nM [35S]GTP gamma S for an additional 30 minutes incubation period. Test compound-induced increase of [35S]GTP gamma S binding by 50 percent or more (250%) relative to the receptor subtype-specific agonist response indicates possible opiate receptor agonist activity. 0.1 uM DPDPE, 1 uM U-69593 and 1 uM DAMGO were used as the specific agonists for the delta, kappa and mu opioid receptors respectively. Opioid receptor antagonist activity was measured using inhibition of agonist-induced increase of [35S]GTP gammaS binding response by 50 percent or more (250%). Nalbuphine, 6-O-mPEG3-Nalbuphine, 6-O-mPEG6-Nalbuphine, 6-O-mPEG9-Nalbuphine were screened at concentrations of 10, 1, 0.1, 0.01 and 0.001 uM in both agonist and antagonist mode. EC50 or IC50 values were calculated from the dose-response curves as a measure of the agonist or antagonist activity of the test compounds respectively.