Prenatal cocaine exposure induces deficits in Pavlovian conditioning and sensory preconditioning among infant rat pups.

Offspring derived from Sprague-Dawley dams that received daily subcutaneous injection of 40 mg/kg.3 cc-1 cocaine hydrochloride (C40) or saline (LC) from Gestational Days 8-20 were tested for first-order Pavlovian conditioning and sensory preconditioning at Postnatal Days 8 (P8), P12, and P21. Although C40 dams gained significantly less weight than LC dams, pup body weights did not differ between the two groups. Significant sensory preconditioning was obtained at P8 and P12 (but not at P21) in LC offspring, confirming previous reports of decline in performance in this task during ontogeny. In contrast, C40 offspring failed to exhibit sensory preconditioning at any test age. In addition, C40 pups tested at P8 did not display significant first-order conditioning. Taken together these results suggest a more general deficit in cognitive functioning rather than a delay in cognitive development in prenatally cocaine-exposed offspring.