INDIVIDUAL-DIFFERENCES IN SUGAR CONSUMPTION PREDICT AMPHETAMINE-INDUCED DOPAMINE OVERFLOW IN NUCLEUS-ACCUMBENS

Rats exhibit individual differences in their consumption of sugar and in their response to amphetamine treatments. Intrinsic variation in th e functioning of the mesolimbic dopamine system is one potential mecha nism underlying the expression of these individual differences. The pr esent experiment examined the relationship between sugar consumption a nd the dopaminergic response to amphetamine. In vivo microdialysis was used to assess amphetamine-stimulated dopamine overflow in the poster ior-medial nucleus accumbens in LOW and HIGH sugar feeders. Sugar cons umption correlated significantly with amphetamine-stimulated accumbens -dopamine overflow. HIGH rats exhibited significantly higher levels of amphetamine-stimulated accumbens-dopamine overflow than LOW rats. The se results suggest that the propensity to ingest sugar is a predictor of the nucleus accumbens dopaminergic response to amphetamine treatmen t.