RESPONSIVENESS TO COCAINE CHALLENGE IN ADULT-RATS FOLLOWING PRENATAL EXPOSURE TO COCAINE

Adult rats that were gestationally exposed to cocaine and control offs pring were examined for their sensitivity to challenge doses of cocain e. Offspring were derived from Sprague-Dawley dams that had received s ubcutaneous injections of 40 mg/kg per 3 cc cocaine hydrochloride dail y on gestational days 8-20, pair-fed dams that were injected with sali ne, and nontreated control darns. In order to investigate the sensitiv ity to challenge doses of cocaine, offspring were assessed in adulthoo d for locomotor activity, cocaine drug discrimination, and the time co urse of cocaine in brain tissue following acute cocaine challenge. Adu lt offspring prenatally exposed to cocaine were observed to exhibit a reduced sensitivity to the discriminative stimulus effects of cocaine as evidenced by a significant shift to the right in the dose-response curve of cocaine discrimination. No prenatal treatment effects were ob served in terms of the temporal patterns of cocaine discrimination or with regard to brain levels of cocaine. In addition, baseline locomoto r activity and locomotor responses to challenge doses of cocaine were comparable across the prenatal treatment groups. Thus, prenatal cocain e exposure reduced sensitivity of offspring to the discriminative stim ulus properties of cocaine without altering either the distribution of cocaine to the brain or the sensitivity of the offspring to the locom otor stimulant effects of cocaine.