PERINATAL COCAINE REDUCES RESPONSIVENESS TO COCAINE AND CAUSES ALTERATIONS IN EXPLORATORY-BEHAVIOR AND VISUAL-DISCRIMINATION IN YOUNG-ADULTRATS

Lister hooded female rats were exposed to either saline or cocaine (20 mg/kg s.c.) from gestational day 10 every other day until weaning (po stnatal day 25). The effects of maternal cocaine exposure on novelty-i nduced exploration and on spontaneous and cocaine-induced motor activi ty were evaluated in young-adult male offspring (4 weeks after weaning ). Rats exposed to cocaine during development spent less lime explorin g two novel objects. Lack of habituation upon the second presentation of the objects and failure in the ability to discriminate between the novel and familiar object were also found in cocaine exposed offspring . Moreover, maternal cocaine treatment did not affect spontaneous moto r activity (active time, average speed and rearing) in rats subjected to an open field test. Furthermore, perinatal exposure to cocaine sign ificantly attenuated acute cocaine (15 mg/kg i.p.)-induced hyperactivi ty. These data indicate that developmental exposure to cocaine, at dos e levels below those producing gross malformations and/or overt signs of neurotoxicity, causes behavioral changes characterized by an altere d responsiveness to environmental and pharmacological challenges.