The ontogeny of SCH 23390-induced catalepsy in male and female rats exposed to ethanol in utero.

The maturation of sensitivity to the cataleptic actions of selective D1 dopamine receptor blockade was assessed in rats exposed prenatally to ethanol. Pregnant rats received an average of 12.68 g/kg body weight of ethanol per day through a liquid diet. Control dams were either pair-fed an isocaloric liquid diet without ethanol or given ad lib lab chow. Separate groups of male and female offspring of these dams were administered either 0.33 or 1.00 mg/kg of the selective dopamine D1 receptor antagonist SCH 23390 at postnatal days 13, 17 or 21, and catalepsy was measured 0, 15 and 30 min later. The results are consistent with a hypothesis that prenatal ethanol exposure alters behaviors mediated by nigrostriatal dopamine systems. Overall, prenatal ethanol-exposed animals showed less catalepsy than control rats. Further, there is a gender effect in that dopamine antagonist-induced catalepsy matures earlier in normal male than in normal female controls. Prenatal alcohol exposure appears to delay the emergence of mature behavioral responses to dopamine blockade in male but not female rats.