Sex-related spatial learning differences after prenatal cocaine exposure in the young adult rat

Prenatal cocaine exposure in humans is associated with a variety of adverse neurobehavioral effects. In the rat, in utero cocaine exposure has been shown to elicit learning impairment during early postnatal development. However, little research has focused on the persistence of these behavioral disruptions. The current study examines the long-term effects of prenatal cocaine exposure on learning performance during young adulthood. Fetal cocaine exposure evoked differential effects in male and female rats on radial-arm maze learning performance. Cocaine-treated females showed significantly impaired choice accuracy during acquisition of radial-arm maze performance when compared to control females. In contrast, cocaine-treated males showed no impairment and in fact showed significantly improved performance on one measure of choice accuracy. For both sexes, this effect was apparent during the final third of acquisition. No evidence was found to suggest altered sensitivity to anticholinergic drugs. While both nicotinic and muscarinic cholinergic antagonists caused significant impairments in memory performance, control and cocaine-exposed rats were effected equally. Single doses of these drugs which caused moderate memory deficits were chosen for use in the current study. The entire dose range should be evaluated to determine the relative sensitivity of cocaine-exposed and control animals to these drugs. The results of this study indicate that there are cognitive effects of prenatal cocaine exposure which persist into adulthood and the sex of the offspring seems to be critical.