Early weaning effects on voluntary ethanol consumption and stress responsivity in rats

The present study examined the effect of early maternal deprivation (early weaning) on voluntary ethanol consumption and responses to cold-immobilization stress in adult rats. Rats were weaned at 16 and 21 days of age and housed individually with food and water ad lib until they reached 190 +/- 5 g at which time half of the animals from each group were exposed to increasing concentrations (3 to 9%) of ethanol in a free choice with water every alternate day. Following acquisition of ethanol drinking, animals were provided with water and ethanol (9%) daily for eight days. At the end of this period, animals were divided into stressed and non-stressed groups. Stressed animals were exposed to cold immobilization stress for 3 hr. Results showed that the early-weaned animals consumed significantly more ethanol as compared to normal-weaned animals. Stomach pathology data revealed little ulcer formation in water-only groups. However, normal-weaned/ethanol-exposed animals exhibited significantly more severe ulcers when compared to all other water- or ethanol-exposed groups. We suggest that early maternal deprivation may predispose animals to increased ethanol consumption as adults. Stress ulcer susceptibility in these animals was likely influenced by interactions among the effects of early weaning, ethanol intake and handling and needs further clarification.