CTAP only partially inhibits the Na
S-induced MOR internalization. SKNMCs are stimulated with DAMGO (1 μM) or Na2S (50 μM) in presence or in absence of CTAP (1 μM) and the effects on MOR activation and internalization are detected. CTAP inhibits the MOR activation induced by DAMGO while it has no effect on that induced by Na2S (panel A). CTAP blocks the DAMGO-induced MOR internalization but, in contrast, it only partially inhibits the Na2S-induced MOR internalization (panel B). Data are representative of at least 3 experiments. *p < 0.05 vs control, **p < 0.05 vs DAMGO alone.