Reduction of learned taste aversions by pre-exposure to drugs.

Taste aversions are induced by a variety of psychotropic drugs. In the present experiments taste aversions induced by the barbiturate hypnotic drug, amobarbital, were dramatically reduced by prior exposure to the drug. Increasing numbers of pre-exposures were associated with larger reductions in taste aversions. Reductions in sleeping time (a widely accepted measure of tolerance to barbiturate drugs) were not correlated with reductions in taste aversions. Taste aversions induced by amobarbital were also impaired following pre-exposure to the pharmacologically dissimilar drug d-amphetamine. These results suggest that reduced taste aversions following pre-exposure to drugs may reflect habituation to drug-related stimuli and not solely the development of tolerance to those drugs.