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HIGH-DOSE ETHANOL INDUCES SECOND-ORDER AVERSIVE CONDITIONING IN ADOLESCENT AND ADULT SPRAGUE-DAWLEY RATS State University of New York at Binghamton, Center for Developmental Psychobiology, Binghamton, NY, 13902-6000. Alcohol abuse and dependence is as a developmental disorder with etiological onset at childhood and adolescence (National Institute on Alcohol Abuse and Alcoholism, 2008). Understanding age-related differences in ethanol sensitivity that can interact with genetic predisposition to promote alcohol abuse and dependence is therefore important. In a previous study, we found that low- to moderate ethanol doses (0.5 and 2.0 g/kg, i.g., Pautassi et al., 2008) induced appetitive second-order place conditioning (SOC) in adolescent, but not adult, Sprague-Dawley rats. The present study assessed motivational effects of high-dose ethanol (3.0 and 3.25 g/kg, for adolescents and adults, respectively) through SOC at postnatal day 34 or 72 (P34 or 72). Ethanol dosage was chosen on the basis of a first Experiment, which found similar blood and brain ethanol levels (circa 200 mg%) in adolescent and adult rats given 3.0 and 3.25 g/kg, respectively. In Experiment 2, animals were administered ethanol or vehicle paired with intraoral pulses of sucrose (CS1, first-order conditioning phase). After one or two conditioning trials, rats were presented the CS1 (second-order conditioning phase) while in a visually and tactually distinctive chamber (CS2). Then, they were tested for CS2 preference. Ethanol-treated animals exhibited reduced preference for the CS2 when compared to controls. This result, indicative of ethanol-mediated aversive place learning, was similar across age (P34 or 72, adolescence or adulthood), sex (female or male) and length of training (one or two trials). The present ethanol doses did not affect behavioral reactivity (wall-climbing and overall locomotion) during the CS1 - CS2 pairings. In conjunction with previous results, the present study suggests that, in adolescent rats and when assessed by SOC procedures, ethanols hedonics change from appetitive to aversive as level of intoxication reaches 200 mg%. Adolescent and adults animals of both sexes seem to perceive the post-ingestive effects of high-dose ethanol as similarly aversive. The SOC preparation can detect learning motivated by both appetitive and aversive sources of reinforcement.