Two drinking bottles were continuously available to individually housed mice. One contained water and the other 15% ethanol (v/v). Bottle positions were changed daily to control for position preferences. Once stable ethanol consumption was reached (see above), we measured ethanol intake after 2 days of saline injections (day 2 in graphs) and grouped mice to provide similar levels of ethanol intake and preference. We measured consumption (g/kg body weight/time) and calculated preference as the amount of ethanol consumed divided by the total amount of fluids consumed per day (a value >50% indicates a preference for ethanol). Bottles were weighed twice daily (see below for time points) for the 24-hour two-bottle choice test. Food was available ad libitum, and mice were weighed every 4 days beginning on day 1. Adult mouse weights are stable, and measuring weight every 4 days is adequate to ensure accuracy; furthermore, no differences in weight between groups were observed during the course of this study. Ethanol consumption was measured after 6 hours and again after the next 18 hours. Measurements made after the next 18 hours
