Lack of difference between HAD and LAD rats in the stimulus generalization of ethanol to nicotine

High alcohol drinking (HAD) and low alcohol drinking (LAD) rats were trained to discriminate 0.5 g/kg ethanol from saline. HAD and LAD rats learned the discrimination at the same rate and to the same level of asymptotic performance. In substitution tests, increasing doses of ethanol produced increased responding on the ethanol lever with dose-effect curves that were very similar in HAD and LAD rats. There was no generalization from ethanol to nicotine, or d-amphetamine, in either HAD or LAD rats. These data may be contrasted with data obtained with alcohol preferring rats (P rats) and alcohol non-preferring rats (NP rats), where the ethanol discrimination was learned more rapidly, asymptotic performance was better in P than in NP rats, and ethanol discriminative stimulus generalized to nicotine and partially to d-amphetamine in P, but not in NP rats. These data suggest that the differences in ethanol consumption reported previously by P and HAD rats relative to NP and LAD rats is not necessarily related to strain differences in ethanol discrimination as the differences in ethanol discrimination previously observed between P and NP rats do not occur in HAD and LAD rats.