New Scientist Heroin addiction gene identified and blocked - Breaking News:
"Scientists have not only identified a critical gene involved in heroin addiction relapse, but they have also successfully blocked it, eliminating cravings for the drug.
The study was conducted on heroin-addicted rats. But the researchers now think that, within a few years, better treatments will become available to human heroin users who cannot quit due to insidious cycles of relapse.
“Many people try to stop taking heroin, but in a few months almost all of them go back to using the drug,” said Ivan Diamond, at the Ernest Gallo Clinic and Research Center in California, US, and one of the research team.
David Shurtleff, director of the Division of Basic Neuroscience and Behavioral Research at the National Institute on Drug Abuse in Maryland, US, is encouraged by the research. “It will take creativity and additional research to translate this into usable therapies, but it does provide hope that we will be able to prevent compulsive drug seeking behaviour,” he told New Scientist.
Previous research has indicated that a section of the midbrain called the nucleus accumbens plays a central role in the “mental reward circuitry” of animals, such as rats and humans. This circuitry generates feelings of pleasure in response to drugs, as well as in response to other things, including food, sex and, in humans, work accomplishments.
Drugs like heroin, however, seem to over-stimulate the normal reward process to the point where users value their next fix more highly than food, water and other essentials. In 2004, a study revealed that cocaine causes a gene in the nucleus accumbens, called AGS3, to rapidly encode masses of proteins that are involved in the cravings and pleasure associated with the drug.
Diamond and his team isolated AGS3 genes and proteins in nucleus accumbens cells taken from newborn baby rats. After cloning and studying the cells in the lab, the researchers determined that AGS3’s drug-related functions are most active in the inner nucleus accumbens core as opposed to its outer shell region.
An AGS3 blocker was then created from a herpes virus. This temporarily binds to proteins within the reward circuit and blocks the cravings-pleasure cycle until the virus “washes out” of the body a few weeks later."