Characteristics of ethanol drinking patterns under schedule-induced polydipsia.

Rats were induced to consume concentrations of ethanol between 5% and 10% (w/v) using the schedule-induced polydipsia technique. Although the substitution of ethanol solutions for water disrupted the usual post-pellet pattern of drinking, large amounts of ethanol were consumed and sound-induced convulsions were observed during ethanol withdrawal. In subsequent experiments, other rats chose 5% and sometimes 10% ethanol solutions over water where both water and ethanol were freely available during the first session of exposure to ethanol. Convulsions and wild running behavior could be observed in some of these rats after only 8 days of drinking, even though ethanol was freely available at all times. Use of the schedule-induced polydipsia technique served to bring the rats into early contact with the ethanol, but rats that received the same number of food pellets in a dish rather than by the schedule drank almost as much ethanol as did the rats receiving ethanol by the schedule. Rats with free access to food pellets drank very little ethanol.