Individual behavioral differences and ethanol consumption in Wistar rats

The aim of this study was to determine if inherent differences in the behavioral measures between individual Wistar male rats influence the level of ethanol consumption. We addressed this question by searching for differences in ethanol intake that an individual animal develops. Measures of ethanol intake were then correlated with the outcome of various behavioral tests. Our results indicate that individual variations of behavioral reactivity may be associated with the predisposition to develop high ethanol intake. Animals with delayed habituation to a novel environment, enhanced locomotor activity during testing in the open field after initial habituation, and excessive locomotor inhibition after administration of 0.07 mg/kg dose of apomorphine, are predisposed to develop high ethanol intake in a free-choice condition. Measures of activity in the forced swim test, apomorphine-induced stereotypy, hypothermia, and locomotor stimulation could not predict a propensity to acquire high ethanol preference. It is suggested that individual differences in the acquisition of high ethanol intake may be influenced, at least partially, by the differences in the sensitivity of brain dopaminergic neurotransmission.