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 the functioning of the mesolimbic dopamine system is one potential mechanism underlying the expression of these individual differences. The present experiment examined the relationship between sugar consumption and the dopaminergic response to amphetamine. In vivo microdialysis was used to assess amphetamine-stimulated dopamine overflow in the posterior-medial nucleus accumbens in LOW and HIGH sugar feeders. Sugar consumption correlated significantly with amphetamine-stimulated accumbens-dopamine overflow. HIGH rats exhibited significantly higher levels of amphetamine-stimulated accumbens-dopamine overflow than LOW rats. These results suggest that the propensity to ingest sugar is a predictor of the nucleus accumbens dopaminergic response to amphetamine treatment.