Figure 4.

The effects of chronic F9202, F9204, DHE, and morphine on cAMP overshoot in CHO-HA-MOR cells. CHO-HA-MOR cells were pretreated with morphine (1 μmol/L), F9202 (1 μmol/L), F9204 (1 μmol/L), and DHE (1 μmol/L) for 24 h at 37 °C. The intracellular cAMP levels were determined as described in the Materials and methods in the presence of 10 μmol/L naloxone. Forskolin-stimulated cAMP accumulation in the absence of opioid agonist was defined as 100%, and the percentage of intracellular cAMP level was calculated from the forskolin control value. Data are presented as means±SEM of at least three independent experiments performed in triplicate. ^cP<0.001 vs DHE-treated group. (one-way ANOVA, Tukey post tests).