Effects of prenatal cocaine on behavioral responses to a cocaine challenge on postnatal day 11

Abstract

The purpose of this study was to investigate the effects of prenatal cocaine treatment on behavioral responsivity to a cocaine challenge on postnatal day (PD) 11. Timed-pregnant Sprague-Dawley rats were injected s.c. with 40 mg/kg/day of cocaine (20 mg/kg twice daily) from gestational day 11 to 20. Saline-control females received saline injections and were pair-fed to the cocaine-treated females, whereas untreated-control females were undisturbed and were fed ad lib. Litters were culled to eight pups on PD1 and fostered to normal lactating dams. On PD 11, subjects were given either saline or cocaine (1.25, 2.5, or 5.0 mg/kg s.c.) and then tested 15 min later for isolation-induced ultrasonic vocalizations and other behaviors. Prenatal cocaine-treated pups showed a reduced sensitivity to the stimulating effect of postnatal cocaine on wall climbing, which may reflect an underlying alteration in central dopaminergic and/or noradrenergic systems. Most of the other behaviors studied, including ultrasonic vocalizations, were unaffected by prenatal cocaine administration. However, one other notable finding was an increase in postnatal mortality among the cocaine-exposed pups. We hypothesize that prenatal cocaine treatment may alter pup behavior so as to produce abnormal maternal-offspring interactions and impaired development in some individuals.