Effect of opioid agonists on MOR/GPR177 interaction. (A) 293-MOR cells were grown either in the absence of drugs (upper panels), or in the presence of 10 μM morphine (middle panels) or 10 μM DAMGO (lower panels) for one hour. Cells were stained with anti-MOR (red) and anti-GPR177 (green) antibodies. Merged images are shown in the right-hand panels. (B) 293-MOR cells were treated with agonist as in A. Cell lysates were immunoprecipitated with anti-MOR antibodies, and immunocomplexes probed with anti-GPR177 antibodies. The bands were analyzed by densitometry and quantitated using ImageJ software. Open bars represent untreated cells, black bars represent morphine-treated cells, and grey bars represent DAMGO-treated cells. Data was analyzed using paired Student's t-test (expressed as mean ± SEM; n = 3, *p < 0.01).