The effect of chronic intermittent ethanol exposure on spatial memory in adolescent rats: the dissociation of metabolic and cognitive tolerances.

Using a rapid chronic intermittent ethanol (CIE) vapor exposure paradigm, we demonstrate the dissociability of metabolic tolerance from cognitive tolerance in adolescent rats. Adolescent rats were trained to spatially navigate in the Morris Water Maze and then exposed to CIE vapor or air 16 h a day for 4 days. After a final 28 h withdrawal, all rats received a saline or ethanol challenge, followed by a test of spatial memory 30 min after administration. Results indicate that CIE vapor exposure did not significantly impair adolescent spatial memory. Although CIE-exposed rats developed metabolic tolerance to a subsequent ethanol administration, CIE exposure did not alter dose-dependent ethanol-induced spatial memory impairments. These data indicate that metabolic ethanol tolerance can be distinguished from cognitive ethanol tolerance during adolescence and suggest that blood alcohol levels alone do not fully explain ethanol-induced spatial memory impairments.