Lever press responding as a measure of ethanol preference in rats.

Preference for ethanol in rats, overcoming the problem of a position habit, was assessed in a one-lever and two-liquid chamber. Performance in lever pressing for ethanol of different concentrations (2.5%, 5.0%, and 15.0%) and for water, as well as the amount of liquid intake, were recorded. Evidence of ethanol preference was observed by both the lever press and consumption measures when the concentration was 2.5%. Water preference was evident at higher concentrations. The present method proved to be a useful method for studying ethanol preference in rats.