DIFFERENTIAL-EFFECTS OF ETHANOL ON MEMORY IN ADOLESCENT AND ADULT RATS

Previous studies have shown that ethanol inhibits memory-related synap tic activity and plasticity more potently in hippocampal slices from i mmature rats, compared with those taken from adults. We therefore hypo thesized that ethanol would more potently attenuate the acquisition of spatial memory in adolescents, compared with adult rats, Adult (65 da ys of age) and adolescent (30 days of age) male rats were given live d aily trials on a spatial memory task in a Morris Water Maze. The anima ls from each age group were subdivided into three subgroups. Each day, thirty minutes before training, the animals in each subgroup were giv en an intraperitoneal injection of 1.0 g/kg of ethanol, 2.0 g/cg of et hanol, or the saline vehicle. Training continued daily until the contr ol animals had reached a performance criterion. Ethanol treatment sign ificantly impaired spatial memory acquisition in the adolescent rats, but did not impair acquisition in adult rats. A separate experiment wi th identical treatment groups showed that ethanol did not impair acqui sition of a nonspatial memory task In the water maze in animals from e ither age group. These experiments show that the acquisition of spatia l, but not nonspatial, memory is more potently impaired by ethanol in adolescent animals, compared with adults.