INCREASED ETHANOL SELF-ADMINISTRATION AFTER A PERIOD OF IMPOSED ETHANOL DEPRIVATION IN RATS TRAINED IN A LIMITED ACCESS PARADIGM

A predominant feature in human alcohol abuse is the reported desire or ''craving'' to consume ethanol along with frequent episodes of drinki ng after periods of abstinence. These and other factors may be respons ible for relapse to uncontrolled ethanol drinking. When relapse occurs after a period of abstinence, ethanol drinking has been shown to be t emporarily increased. Two aspects of drug dependence could contribute to these increases. One may be the development of a need state; the ot her may involve changes in the perception of the positive reinforcing effects of ethanol when reinforcer access is limited. To investigate t his phenomenon further, the present study was conducted to examine in nondependent rats the effect of forced time-off on oral ethanol self-a dministration in a limited access paradigm (30 min/day). Male Wistar r ats were trained to respond for ethanol (10% w/v) or water in a two-le ver, free-choice condition using a saccharin fading procedure. After t he establishment oi stable baseline responding for ethanol, various et hanol deprivation periods (3, 5, 7, 14, or 28 days) were imposed, duri ng which no ethanol was available. Responding for ethanol increased as a function of the duration of the deprivation period when compared wi th baseline levels. This increase was temporary and returned to baseli ne levels within 2 to 3 days. Given that the shortest time-off period was 5 days and the rats showed no signs of withdrawal, this transient increase in ethanol responding does not seem to be related to the mani festation of dependence and withdrawal, and may be related to changes in ethanol's reinforcement properties. These results with rats may pro vide ii useful tool to elucidate mechanisms underlying human alcohol s eeking behavior and relapse.