Effect of ingestion-contingent hypothermia on ethanol self-administration

This study tested the hypothesis that ethanol intake and preference for ethanol-paired flavors are inversely related to the magnitude of hypothermia induced by ethanol. Fluid-deprived rats were given 15-min daily access to 7% ethanol in one of two flavored saccharin solutions. Consumption of one flavored ethanol solution (counterbalanced) was consistently followed by 6-hr placement in a room maintained at 32 degrees C, whereas, consumption of the other flavored ethanol solution was followed by maintenance at room temperature (21 degrees C). Animals experienced less hypothermia when ethanol was followed by exposure to 32 degrees C and eventually drank more of the flavored ethanol that preceded this exposure. Moreover, intermittent two-bottle choice tests revealed development of a preference for the flavor that preceded exposure to 32 degrees C. An "extinction" phase indicated that this preference was not due to association with the thermal environments, but depended on differences in ethanol-induced hypothermia. These results support the conclusion that oral intake of ethanol is modulated by ethanol-induced hypothermia, most likely through a conditioned taste aversion mechanism.