The results of this experimental series demonstrate that adolescent animals consume significantly more ethanol than adult animals under a variety of home cage continuous-access circumstances, with the relatively greater intake of adolescents further magnified by a number of test conditions. Subtle experimental details often thought to be innocuous can have a substantial impact on overall amount of voluntary ethanol consumption observed in both adolescent and adult animals.

Adolescent rats have been reported to be less sensitive than adults to many acute ethanol effects, including ethanol-induced sedation and motor impairment, but conversely more sensitive to ethanol-induced disruptions in spatial memory in a Morris water maze (Markwiese et al., 1998). The present study examined adolescent and adult rats trained for 6 days under spatial or nonspatial versions of a presumably less stressful sand box maze. Moderately food-deprived animals were given 0, 0.5, or 1.5 g/kg ethanol intraperitoneally 30 min before training each day, but were tested without ethanol or reinforcer on test day. Spatial acquisition was impaired by 1.5 g/kg in adults but not adolescents, with no ethanol impairment on the nonspatial task at either age. These results are opposite the ontogenetic profile reported by Markwiese et al., (1998) and may reflect differential activation of prefrontal cortex or other stress-sensitive forebrain regions by the two tasks across age.