Historical factors in the development of ETOH-conditioned place preference

Three groups of male Sprague-Dawley rats were conditioned with ethanol (ETOH) and water in a Conditioned Place Preference task. To assess the contribution of prior drug/behavioral history on the relative hedonic valence of ETOH, the three groups differed in the task demands and degree of prior ETOH exposure. One group was trained to self-administer 20% w/v ETOH in a home-cage self-administration task using a "Samson sucrose-fading" procedure prior to place conditioning trials (Group SA/CPP). A second group was initially trained in a two-choice ETOH-Saline drug discrimination (DD) task and subsequently conditioned in the place preference paradigm (Group DD/CPP). The third group of rats had no history of drug exposure and were experimentally naive prior to the place learning task (Group NH/CPP). Group SA/CPP developed a significant conditioned place preference; Group DD/CPP failed to demonstrate either a preference or aversion, whereas the Group NH/CPP demonstrated a significant place aversion. Data suggest that both present and past contingencies contribute to the algebraic summation of ETOH's hedonic valences.