PRENATAL COCAINE BUT NOT PRENATAL MALNUTRITION AFFECTS FOSTER MOTHER PUP INTERACTIONS IN RATS

The separate and combined effects of prenatal cocaine exposure and mal nutrition on mother-pup interactions in rats were assessed daily from postnatal day 2 to day 21. Sprague-Dawley darns were fed a diet of low protein content (6% casein), an isocaloric diet of adequate protein c ontent (25% casein, control), or a laboratory chow diet prior to matin g and throughout pregnancy. Within each diet group, rats received eith er cocaine injections (30 mg/kg IP two times per week prior to mating and then 30 mg/kg SC daily from days 3 to 18 of pregnancy) or saline i njections. Litters were fostered on the day of birth to control mother s (i.e., nondrug-exposed darns fed the control or chow diet). Foster m others fed the 25% casein diet showed increased contact with cocaine-e xposed pups compared with nondrug-exposed pups in the second postnatal week but lower levels as the pups approached weaning. Passive nursing was increased in dams caring for prenatally malnourished, cocaine-exp osed pups compared with those caring for similar pups with no drug exp osure. Chow-fed mothers did not differ in their behavior towards pups with or without prenatal cocaine treatment. Prenatal cocaine and malnu trition independently compromised birth weight and various reflexive m ilestones but the attainment of physical milestones was affected only by prenatal cocaine. There were no additive effects of the two prenata l insults on any measure of mother-pup interaction or pup development.