Prenatal cocaine exposure: effects on play behavior in the juvenile rat.

Prenatal exposure to cocaine has become a growing problem in the United States. This study examined the effects of such exposure on social behavior in young rats. The subjects were offspring of Sprague-Dawley dams exposed to 40 mg/kg cocaine HCl (SC) daily on gestational days 8-20, pair-fed dams injected daily with 0.9% saline, and saline-injected controls. The pups were tested at 28, 30, 32, 34, and 36 days of age for instances of pinning, a reliable measure of play behavior. Although showing no differences on such developmental indices as body weight or age of eye opening, offspring prenatally exposed to cocaine showed significantly less pinning than saline controls and were more likely to be pinned. Although males pinned more than females across the treatment groups, cocaine-exposed rats of both sexes showed play deficits. Gestational cocaine exposure thus appears to result in suppressed levels of play in juvenile rats.