A different way of gene expression in the brain is responsible for deterioration in heroin-addicted rats

A group of genes whose expression changes significantly following a period of sudden drug abstinence in addicts has been identified

A group of genes whose expression changes significantly following a period of sudden drug abstinence in addicts has been identified. In a study published in the open journal BMC Neuroscience, they studied gene expression in the brains of rats addicted to heroin, and concluded that these genes are involved in accelerating the deterioration process.

Cara Koontz-Melkabage from the Pennsylvania State University School of Medicine is part of the team of researchers who performed the experiment. She says: "In the past, the changes in a number of gene expressions caused by exposure to a drug were extensively studied, but only very few studies described the deterioration after a sudden cessation of exposure to the drug. We have identified 66 genes involved in the deterioration response, including some very important genes for neural flexibility, and through changes this may affect learning ability and behavior.

Koontz-Melkabge and her colleagues administered drugs to rats for three hours a day for two weeks whenever they drank from a tube, while a control group received saline. One group of addicted rats was deprived of the drug for two weeks before they returned to sipping from the tube, which no longer provided them with drugs. After 90 minutes in an environment that reminds them of the addiction, where the addicted rats tried to lick the empty tubes, some of the rats in the addicted group and the control group were killed (humane death, the researchers assure), and the gene expressions in their brains were examined. By comparing the gene expression in the addicted rats that were exposed to the narcotic environment even after one day of deprivation, with those in the control group, the researchers were able to identify the genes involved in the deterioration process following forced withdrawal.

According to Koontz-Melkavage, "The control using the empty tube served not only to provide us with an opportunity to observe the behavior of drug addicts when they lack it, but also to mimic a real-life situation where environmental cues accelerate the process of deterioration following a long period of dryness.

"As data accumulates, the existence of a single gene responsible for deterioration during sudden weaning becomes unlikely. It is more likely that there is a set of different genes. Therefore, a more comprehensive look at gene expression, such as the one we performed, could be useful to guide researchers investigating drug-related behavior in humans."

to the notice of the researchers