Adult, male, ethanol-naïve, SD rats weighing 150–175g upon arrival (Charles River, Wilmington, MA USA), were individually housed in ventilated Plexiglas cages (Thoren Caging Systems Inc., Hazelton, PA, USA) in a climate-controlled room on a 12-h reverse light/dark cycle (lights off at 10 a.m.). Rats were given at least 1 week to acclimate to individual housing conditions and handling procedures. Food and water were available ad libitum in the home cage throughout the entire experiment. Operant-sessions occurred between 12 and 4 PM, with the exception of initial self-administration training as outlined below. All procedures were pre-approved by the Ernest Gallo Clinic and Research Center Institutional Animal Care and Use Committee and were in accordance with NIH Guide for the Care and Use of Laboratory Animals.
