Two-bottle drinking procedure

Detailed protocol for two-bottle drinking procedure

According to previous investigational study, the C57BL/6J strain was appropriate to evaluate voluntary ethanol intake among 15 inbred mice (doi: 10.1007/BF02244901). During the 1-week acclimation period, mice were adapted to two-bottle choice procedure (two graduated cylinders containing tap water). After division of mice to each group randomly, ethanol administration group was adopted to 5% ethanol containing bottle and tap water containing bottle for 3 days to familiarize with initial ethanol exposure. Then mice were allowed to freely intake 10% ethanol or tap water for 28 days, with the exchanging two bottles position to avoid a positional preference at 4-days intervals.