Recently, scientists have developed a more sophisticated understanding of the ways in which genetics influences a person's health. The complement of genes a person inherits at birth is, of course, essential. But all genes are not created equal; only some genes are "expressed"—that is, actively participate in protein production. Today, a new field of scientific inquiry, called epigenetics, investigates the cellular mechanisms that control gene expression and its impacts on health and behavior.

Epigenetic processes allow experience to influence cellular processes. For example, epigenetic alterations that accumulate during a person's lifetime can contribute to aging, the development of cancer, obesity, and other health conditions.

NIDA is funding studies to learn how epigenetic mechanisms figure in the neurobiology of drug abuse and addiction. In a dozen projects, researchers are elucidating the links between exposure to drugs of abuse, epigenetic processes, gene function, and neurobiological and behavioral changes in animal models of addiction. A recent study, for example, showed that cocaine triggers an epigenetic process called chromatin remodeling and that this contributes to rats' behavioral responses to the drug ("Gene Experiment Confirms a Suspected Cocaine Action"). Cocaine-induced epigenetic changes may increase the number of neural connections between the reward pathway and other brain regions that regulate emotions and memories to drive craving. We see every reason to hope that increased understanding of drugs' effects on epigenetic processes in the brain will open the door to analogous new addiction therapies.

National Institutes of Health (NIH) Director Dr. Elias Zerhouni has charged NIDA with a key role in developing a program within the NIH Roadmap Initiative on epigenomics—the analysis of epigenetic changes across a species' entire genetic blueprint. This agency-wide effort aims to provide researchers with standard tools and technologies to develop comprehensive epigenome maps that potentially will point the way to more effective responses to a wide range of health problems. To learn more about the Roadmap Epigenomics Program, visit nihroadmap.nih.gov/epigenomics/index.asp.

Volume 21, Number 5 (March 2008)