Appetitive motivational experience during adolescence results in enhanced alcohol consumption during adulthood

Exposure to alcohol during adolescence is predictive of adult alcohol abuse and dependence. The present experiment was designed to measure the impact of appetitive motivational engagement with ethanol during adolescence on adult ethanol consumption. To this end, a group of adolescent male Wistar rats was allowed to traverse an operant runway to obtain access to a sweetened 10% ethanol solution (wt/vol) over 18 sessions. An additional yoked-control group was allowed access to an identical solution; however, exposure to the solution was contingent on the experimental groups entry into the goal box of the runway. Once the adolescent exposure sessions were completed, the animals were allowed to mature into adults and then tested for differences in ethanol consumption during 30-min 2-bottle limited access sessions. Following 14 ethanol consumption sessions during adulthood, a naltrexone dose-response challenge (0-0.4 mg/kg) was initiated for both groups. The results of the experiment showed that the animals allowed to traverse the runway during adolescence displayed increased ethanol consumption during adulthood when compared to the yoked-control group. In addition, both groups showed dose-dependent attenuation of ethanol consumption by naltrexone. Thus, appetitive motivational experience during adolescence can impact adult ethanol consummatory behavior, a process that appears to involve common reinforcement-related neural substrates. This model should prove useful in delineating appetitive motivation-related factors that contribute to excessive ethanol consumption.