Cocaine- and Amphetamine-Regulated Transcript (CART) Peptide and Drug Addiction

Drug addiction is a brain disease that involves the disruption of important brain neurocircuitry. One important brain system implicated in drug addiction is the mesolimbic system, which includes dopaminergic projections from the ventral tegmental area to the nucleus accumbens (NAc). Within the NAc are neurons containing cocaine- and amphetamine-regulated transcript (CART) peptide, which interacts with the mesolimbic dopaminergic system. This interaction may indicate that CART peptide is involved in drug abuse and addiction. In support of this idea, several studies have shown that endogenous and exogenous changes in the concentrations of CART peptide in the NAc modulate dopamine- and cocaine-mediated behavioral effects. CART peptide also modulates some of the behavioral effects of other drugs of abuse such as amphetamine and ethanol. While the CART peptide receptor has not yet been cloned and characterized, understanding CART peptide pharmacology may enable us to better understand the mechanisms involved in drug addiction.