Inhibition of forskolin-stimulated cAMP accumulation by opioids in hMOR-1 variantsa.

aThe IC50 and maximal inhibition were calculated by nonlinear regression analysis using Prism 4.0, GraphPad Software. Results are means ± S.E.M. of 3–7 independent determinations. Maximal inhibition: Maximal inhibition was determined after correcting for different receptor expression levels by western blot analyses (Figure S3). The expression levels of receptor variants were calculated relative to that of hMOR-1 (which was set to 1). Significant differences in maximal inhibition were observed for DAMGO (pIC50: Significant differences of IC50 were observed for DAMGO (p50 value of hMOR-1 differed from hMOR-1A2 (p50 value of hMOR-1 differed from hMOR-1A2 (p50 value of hMOR-1 differed from hMOR-1A2 (p