Complete reversal of chronic ethanol polydipsia by schedule withdrawal.

Rats exposed to daily 3-hr intermittent food delivery sessions (binging) chronically ingested excessive amounts of either H2O or 5% EtOH (mean 7.1 g/kg/3-hr). Withdrawing the intermittency of the feeding schedule once every 10 days (single-ration probe session) resulted in reduction of fluid intakes (both H2O and EtOH) to the level of animals always given daily single-ration sessions. This complete dependence of elevated fluid intake levels on the intermittent feeding schedule was unaffected by either the number of probes previously administered (0 to 11) or the duration the feeding schedule was maintained before introduction of the first probe session (29 or 109 days). The results of the probe sessions demonstrated that a history of ethanol overindulgence was not a sufficient condition for the maintenance of overdrinking. Continued overindulgence required the continued presence of the original inducing conditions. Ethanol-polydipsic animals exposed to periodic probe sessions also developed a slow rise in binge session intake. No such increase was observed in the water-polydipsic animals.