Scientists have discovered a key mechanism in the brain that helps to explain the addictiveness of cocaine, according to new research funded by the National Institute on Drug Abuse (NIDA), which is part of the National Institutes of Health.

The study, which is published in the January issue of the journal Science, demonstrates who cocaine affects an epigenetic process call histone methylation. An epigenetic process is a process that is capable of influencing gene expression without changing a gene's sequence. The changes caused to this process by cocaine affect the brain's pleasure circuits and are likely to contribute to an acquired preference for cocaine.

For the study, researchers studied the effects of chronic cocaine exposure in young mice. The researchers gave one group of young mice repeated doses of cocaine, while a control group received repeated doses of saline solution with a final dose of cocaine. The researchers then examined how one-time exposure to the drug differed from chronic exposure. The study confirmed that chronic exposure alters the brain's reward pathway.

NIDA Director Dr. Nora Volkow commented on the findings: "This fundamental discovery advances our understanding of how cocaine addiction works. Although more research will be required, these findings have identified a key new player in the molecular cascade triggered by repeated cocaine exposure, and thus a potential novel target for the development of addiction medications."

Dr. Eric J. Nestler, study investigator and director of the Brain Institute at Mount Sinai School of Medicine, commented: "The more complete picture that we have today of the genetic and epigenetic processes triggered by chronic cocaine give us a better understanding of the broader principles governing biochemical regulation in the brain which will help us identify not only additional pathways involved but potentially new therapeutic approaches."

(Source: www.sciencedaily.com)

Labels: addiction, cocaine