EFFECTS OF CHRONIC AND ACUTE COCAINE TREATMENT ON THE ONSET OF MATERNAL-BEHAVIOR AND AGGRESSION IN SPRAGUE-DAWLEY RATS

Pregnant rats were treated either throughout gestation (GD 1-20) with 30 mg/kg per day (chronic cocaine) or with one 15-mg/kg dose immediate ly following parturition (acute cocaine). Chronic and acute cocaine tr eatment delayed or diminished the postpartum onset of some components of maternal behavior, and chronically treated dams were significantly more aggressive toward a male intruder than acute cocaine-treated or s aline-treated dams. Cocaine increased the latency to crouch over pups and decreased crouch duration during a 30-min observation period that immediately followed parturition. Latencies to nest build were also lo nger in more chronic cocaine-treated dams than in saline controls. On Day 6 postpartum, 83% of chronic cocaine-treated dams pinned and attac ked an intruder male 8 or more times during a 10-min observation perio d, whereas only 4% of acute cocaine-treated and none of the saline-tre ated dams exhibited this much aggression.