Facilitation and inhibition of feeding by a single dose of amphetamine: relationship to baseline intake and accumbens cholecystokinin

Abstract

Amphetamine (AMP) administered in high doses suppresses feeding. However, in low doses AMP has been shown to both suppress and facilitate feeding. Further, there is some indication of individual differences in the feeding response to low doses of AMP. Evidence indicates that AMP's effects on feeding are dopamine-mediated and that the nucleus accumbens (Acb) may be an important site of action. Of interest here is the fact that CCK terminals exist within the Acb and CCK modulates DA activity. Experiment 1 investigated the effects of intra-Acb CCK administration as a function of individual differences in the feeding response to a low dose of systemic AMP. Results indicate that response to AMP was baseline dependent. AMP stimulated feeding in low baseline feeders and suppressed feeding in high baseline feeders. Intra-Acb CCK blocked the AMP-induced increase in feeding but not the AMP-induced anorexia. In experiment 2, the effects of intra-Acb CCK administration on baseline feeding were assessed. Intra-Acb CCK suppressed baseline feeding, but only when there was a high level of intake. It is speculated that Acb-DAergic activity may play a role in the observed feeding effects of both AMP and CCK.