Some determinants of the motivational properties of ethanol in the rat: concurrent administration of food or social stimuli.

The hypothesis was examined that the interaction of ethanol with the conditions under which it is administered may determine whether either preference or aversion for the drug develops. In Experiment 1, eight groups of food-deprived rats received injections of ethanol (175-1,400 mg/kg) in one environment and were later offered a choice between that environment and a different one previously associated with saline injections. Another eight groups were treated identically, except that food was available in both the saline and ethanol-paired environments. The groups given the drug without food showed no preference or aversion at low doses (175-700 mg/kg), but showed aversion at higher doses (1,000 and 1,400 mg/kg). When food was available, there was an increased preference for the environment paired with the 500 mg/kg dose and reduced aversion at the 1,000 and 1,400 mg/kg doses. In Experiment 2, placing two rats together increased each rat's preference for the environment associated with the other animal. However, rats pretreated with 500 mg/kg ethanol before being placed together showed a reduced preference for the environment associated with the drug and the other animal. Controls never paired with another rat showed no preference or aversion at the same ethanol dose. Thus, ethanol may interact with conditions such as the presence of food or another animal to determine final effects that are unique to those conditions.