COCAINE ALTERS THE ONSET AND MAINTENANCE OF MATERNAL-BEHAVIOR IN LACTATING RATS

Though much attention has been devoted to the behavioral and physiolog ical consequences of cocaine abuse in offspring, little is known regar ding the effects on the maternal behavior of the cocaine-exposed dam. We examined whether cocaine affects the initiation (late pregnancy) an d/or maintenance (postpartum [PP]) phases of full maternal behavior (F MB; retrieving, grouping, and crouching over six pups) in Sprague-Dawl ey female rats. In Experiment 1, cocaine (5.0 or 10.0 mg/ kg) or salin e was administered on PP day 5 err 6 and FMB scored. Both dosages sign ificantly disrupted FMB, particularly crouching, though 10.0 mg/kg had a greater effect on FMB. Experiment 2 (using 10.0 mg/kg cocaine) exam ined specific elements of the disruption and found significant reducti ons in proportion of females engaging in FMB, as well as increases in the latencies to contact, retrieve, lick, group, and crouch over pups. In Experiment 3 osmotic pumps containing 20 mg cocaine/kg/day or sali ne were implanted SC in day 14 pregnant rats. FMB testing was performe d on days 1-2 postpartum together with a T-maze pup-retrieval test on postpartum days 3-5. Cocaine disrupted FMB in the homecage, in general , rendering the females less attentive to young, but was without effec t in the T-maze tests. Cocaine-perhaps owing to its purported dopamine rgic activity - may operate through motivational mechanisms to disrupt FMB in the postI?artum maintenance phase; and through effects on late pregnancy levels of prolactin (a hormone which stimulates FMB), to di srupt maternal behavior during the initiation phase.