Rotation, locomotor activity and individual differences in voluntary ethanol consumption

Spontaneous turning behavior and locomotor activity were evaluated for thei r ability to predict differences in the voluntary consumption of ethanol in male Long-Evans rats. Animals were assessed for their preferred direction of turning behavior and for high vs. low levels of spontaneous locomotor ac tivity, as determined during nocturnal testing in a rotometer. Subsequently , preference for a 10% ethanol solution vs, water was determined in a 24-h two-bottle home-cage free-choice paradigm. Rats exhibiting a right-turning preference consumed more ethanol than rats showing a left-turning preferenc e. While locomotor activity alone did not predict differences in drinking, turning and locomotor activity together predicted differences in ethanol co nsumption. Low-activity right-turning rats consumed more ethanol than all t he other groups of rats. Previous studies from this laboratory have shown t hat individual differences in turning behavior are accompanied by different asymmetries in dopamine (DA) function in the medial prefrontal cortex (mPF C). Individual differences in locomotor activity are associated with differ ences in nucleus accumbens (NAS) DA function. The present data suggest that variations in mPFC DA asymmetry and NAS DA function may underlie differenc es in the voluntary consumption of ethanol. (C) 1999 Elsevier Science B.V. All rights reserved.