A procedure to produce high alcohol intake in mice

Rationale: While prolonged access to ethanol (EtOH), or deprivations, or their combination have occasionally been shown to yield high levels of voluntary self-administration, in almost all cases, rodents do not self-administer alcohol to the degree that they will develop substantial, intoxicating blood alcohol levels and then continue to self-administer at these levels. Objectives: The purpose of the present series of experiments was to modify a fluid restriction procedure to demonstrate consistent, high EtOH consumption. Methods: Male and female mice from an alcohol preferring inbred strain (C57BL/6J; B6) as well as from a genetically heterogeneous strain (WSC) were given varying periods of access to fluid, ranging from 90 min to 10 h per day, for 12-21 days. Every 3rd or 4th day, separate groups of mice were offered a 5, 7 or 10% EtOH solution for either 10 min or 30 min, followed by water for the remainder of the time. Results: In all studies, stable high EtOH doses were consumed by both B6 and WSC mice across the EtOH sessions, exceeding 2 g/kg in a 30-min session. Mean blood EtOH concentration exceeded 1 mg/ml (i.e. 100 mg%), with values in individual animals ranging from 0.6 mg/ml to 3.4 mg/ml. Notably, mice receiving 10 h of fluid/day continued to consume 2 g/kg doses of EtOH. While this procedure did not produce subsequent preference for EtOH in WSC mice, consumption remained high in some animals. Conclusions: These data indicate that scheduling fluid intake produces high, stable EtOH consumption and BEC in male and female B6 and WSC mice.