Sex Differences in Ethanol Intake and Sensitivity to Aversive Effects during Adolescence and Adulthood

Aims: The present experiments examined sex differences in ethanol intake and in the influence of a social context on aversive properties of ethanol in adolescent and adult Sprague-Dawley rats. Methods: Experiment 1 examined ethanol intake, with animals receiving daily 2-h access to ethanol and water for 8 days. Experiment 2 assessed the aversive effects of ethanol using a conditioned taste aversion (CTA) paradigm, with animals placed either alone or with a same-sex, same-age peer during the ethanol intoxication phase of conditioning. Results: Ethanol intake varied with both age and sex, although the sex differences emerging at each age were opposite in nature. Adolescent males consumed more ethanol relative to their body weights than adolescent females and adults of both sexes, whereas adult females generally consumed more than adult males. The CTA test revealed no sex differences in aversive effects of ethanol in adults, whereas adolescent males were less sensitive to the aversive properties of ethanol than adolescent females when intoxication occurred in the presence of a peer. Ethanol-induced CTA was evident in adults at lower doses than in adolescents. Conclusions: These results suggest that age differences in ethanol intake in males and sex differences in intake during adolescence may be associated in part with the relative insensitivity of the male adolescents to ethanol's aversive properties, especially when intoxication occurred in a social context. However, the elevated ethanol intake observed in adult females relative to their male counterparts appears to be unrelated to the aversive properties of ethanol.