A new study suggests that the molecular basis for cocaine's "rewarding" effects on the brain is more complicated than scientists thought (Proc Natl Acad Sci U S A. 1998;95:7699-7704).
Studies had indicated that 2 key proteins, dopamine and serotonin transporters, were associated with the rewarding and reinforcing effects of cocaine. However, investigators at the National Institute on Drug Abuse (NIDA) discovered that cocaine could still elicit drug-seeking behavior in strains of genetically altered "knockout" mice that lack the genes for these transporters.
Stephenson J. Cocaine and the Brain. JAMA. 1998;280(7):594. doi:10.1001/jama.280.7.594-JHA80006-3-1