Development of a mouse model of ethanol addiction: naltrexone efficacy in reducing consumption but not craving

The aim of the present study was validating pharmacologically a mouse model of alcohol addiction. Mice (n = 60) were offered ethanol (5% and 10%) and water in a free choice paradigm consisting of four phases: free choice (10 weeks), withdrawal (2 weeks), re-exposure (2 weeks) and quinine- adulteration (2 weeks). Control mice (n = 10) had access to water. They were housed individually with food ad libitum. The animals' behaviour was evaluated at the beginning of the treatment and during the withdrawal period. After the exposure to the model, mice received i.p. naltrexone (0.0; 0.125; 2.0 and 16.0 mg/kg) or saline. Mice were characterized as: addicted (n = 15, preference for ethanol without reducing intake when ethanol were adulterated with quinine); heavy drinker (n = 14, preference for ethanol but reduced intake when ethanol were adulterated); and light drinker (n = 16, no preference for ethanol). Naltrexone reduced ethanol intake in the heavy and light groups (p