Figure 3.

Inhibition of FSK-stimulated cAMP accumulation by morphine (1 μM). cAMP levels in FLAG-MOP/TRPV1 double stable colonies were measured using an enzyme-immunoassay kit either in unstimulated cells (no FSK), or in cells treated with FSK (50 μM) and IBMX (100 μM). Morphine (1 μM) significantly reduced cAMP levels in FSK-stimulated cells (morphine) compared to stimulated cells treated with water (vehicle). Morphine inhibited cAMP production by 67.0 ± 4.6% for FLAG-MOP/TRPV1 colony 13 (dotted bars) and 79.2 ± 7.4% for colony 21 (cross-hatched bars). Data are presented as mean ± SEM from n = 3 samples read in triplicate. ** p < 0.01 compared to vehicle.