Persistent High Alcohol Consumption in Alcohol-Preferring (P) Rats Results from a Lack of Normal Aversion to Alcohol

摘要

>Aims: In this study, we tested the impact of pretreatment with alcohol on subsequent alcohol drinking in outbred Sprague–Dawley and selectively bred alcohol-preferring (P) rats. >Methods: As a pretreatment, male Sprague–Dawley and P rats were given a passive oral administration of either alcohol (1.0 g/kg) or tap water. Then, they were given free choice of drinking alcohol (5% v/v) or water in their home cages, which was measured over 4 weeks. >Results: Without alcohol pretreatment, there was no significant strain difference in alcohol preference; both strains preferred 5% (v/v) alcohol solution. The strain difference was only apparent in the groups given alcohol pretreatment. This arose from the fact that alcohol pretreatment significantly reduced alcohol preference in the Sprague–Dawley rats to a level well below 50%, while it did not alter drinking behavior in P rats. The same effects were seen with total alcohol consumption (g/kg/day). These effects persisted throughout the 4 weeks of the study. >Conclusions: The principal difference between the Sprague–Dawley and P rats was that the P rats did not show the normal aversion to alcohol after forced exposure to alcohol that the Sprague–Dawley rats showed. One of the potential contributors to high alcohol intake and preference in P rats may be lack of sensitivity to aversive effects of alcohol.