Tag : Epigenetic

South Carolina (USA): Physical reliance on the drug by the body as well as negative experiences from previous drug use might lead to a relapse into regular drug usage. Uncertainty still exists over how these drug associations are created in the brain and how they lead to a relapse. "Individuals make long-lasting associations between the euphoric experience of the drug and the people, places and things associated with drug use," said Christopher Cowan, Ph.D. professor in the Department of Neuroscience at the Medical University of South Carolina (MUSC) and member of the Brain and Behavior Research Foundation Scientific Council. Cowan and his team report in the Proceedings of the National Academy of Sciences (USA) that an enzyme known as histone deacetylase 5, or HDAC5, plays a significant role in limiting heroin-associated memories and drug-seeking behavior following a period of abstinence in rats. The study, revealed HDAC5 as a target of interest in treating vulnerability to return to drug use in opioid use disorder. HDAC5 is an "epigenetic" enzyme, meaning it can influence the expression of many different genes. HDAC5 is active in the brain and has been associated previously with resumed cocaine use after a period of abstinence. "In a prior study, we showed that HDAC5 is regulated by cocaine, and it reduces the impact of substance use triggers following cocaine use," said Cowan. "In the new study, we wanted to learn why HDAC5 had these effects and if they were specific to cocaine or perhaps generalizable to other classes of addictive drugs, like opioids." Cowan examined drug-seeking behaviors by modelling a return to opioid use in rats after a period of abstinence from self-administration of heroin, a commonly used opioid drug. ...