Dopamine turnover as determined by the DOPAC-to-dopamine (DA) ratio in the prefrontal cortex, nucleus accumbens, and striatum of rats. Rats were pretreated with either clonidine (CLON; 0.1 mg/kg) or vehicle at 45 min and FG7142 (FG; 30 mg/kg) or vehicle (VEH) at 30 min before killing. Data are expressed as mean ± SEM. *p < 0.05 versus vehicle.