Mesolimbic gender differences in peptide CART mRNA expression: effects of cocaine

THE putative neurotransmitter peptide CART has been suggested to be involved in the actions of psychostimulants. We analyzed the CART mRNA expression in mesolimbic brain areas of male and ovariectomized 17β-estradiol- (30 μg) and vehicle-treated female rats. A gender difference was noted in the accumbens shell during basal conditions; male rats expressed higher levels of CART mRNA than both female groups. Following binge cocaine injections (3 × 15 mg/kg), elevated levels were found in the central amygdala of male but not female rats. In the medial accumbens shell CART mRNA was elevated after cocaine, but only in the non-treated females. The present results support a role of mesolimbic CART in psychostimulant drug action.