New Mechanism Underlying Cocaine Use Discovered
In a January 7 news release from the U.S. National Institute on Drug Abuse (NIDA), U.S. government scientists announced the identification of a brain mechanism that helps to explain cocaine addiction.
The study consisted of two groups of mice; one group was given repeated doses of cocaine, while the other group received repeated doses of saline. The final dose for each group consisted of cocaine, in order to examine differences between chronic and one-time cocaine exposure.
Researchers found that cocaine affects an epigenetic process in the brain - a process that can influence gene expression without changing gene sequence. Chronic cocaine exposure alters the brain's reward pathway by repressing G9A, an enzyme that plays a key role in gene expression. This confirms the results of prior studies showing that chronic cocaine exposure leads to alterations in gene expression and the development of a strong preference for cocaine. More importantly, researchers were able to show for the first time that changes in gene expression and enhance preference for cocaine can be inhibited by reversing the cocaine-induced repression of the enzyme G9A.
What Does This Mean?
"This fundamental discovery advances our understanding of how cocaine addiction works," says NIDA Director Dr. Nora D. Volkow. This newly identified mechanism is a potential target for the development of medications to treat cocaine addiction, in addition to providing insight into the processes behind addiction. Dr. Eric J. Nestler, study investigator, explains that "The more complete picture we have today...will help us identify not only additional pathways involved but potentially new therapeutic approaches."