Effects of alcohol deprivation on alcohol consumption using a sipper-tube procedure

Background: When rats with prior experience drinking ethanol solutions are deprived of ethanol for various lime periods, a transitory increase in alcohol consumption is observed when ethanol solutions are again made available. This has been termed the alcohol deprivation effect (ADE). The ADE has been observed in limited-access operant procedures in which small dippers of ethanol are presented following completion of a lever press requirement. However, it has not been determined if the effect occurs in an operant model of ethanol self-administration that separates the ethanol-seeking responding from the consummatory drinking (the sipper procedure). Methods: Rats were initiated to drink ethanol from a sipper tube using the sucrose-substitution procedure. Once initiated, the rats had to make 30 lever presses to gain access to a sipper-tube containing the ethanol solution for 20 min. The effects of 2-3 days, 7 days, and 14 days of ethanol deprivation were examined on ethanol consumption and extinction responding (seeking response). Results: There were no effects of deprivation on intake at any deprivation period examined. Contrary to expectations, the alcohol-seeking response as measured by extinction responding was decreased after 7 and 14 days of deprivation. Conclusions: The data from this study and others using the limited access operant procedures suggest that the ADE may be more related to consummatory control (i.e., loss of control) and not to ethanol-seeking behaviors (i.e., craving).