Addiction Relapse Prevented by Deactivating Brain Trigger: No Memory of Alcoholism

Addiction affects thousands of people across the United States and throughout the world. In fact, about one in every 12 adults suffers from alcohol abuse in the U.S.--that's 17.6 million people. Now, though, researchers have identified and found a way to deactivate a brain pathway linked to memories that causes alcohol cravings in rats. The findings could one day lead to a better treatment option for those that suffer from alcoholism and other addictions.

During the course of the study, the researchers allowed rats to either freely drink water or alcohol over the course of seven weeks. During this time, the rats developed a high preference for alcohol, essentially becoming addicted. Then the researchers made it so that the rats only had access to alcohol for one hour a day; the rats had to press a lever to access it during a certain time period. After that, the researchers cut the rats off from alcohol entirely.

The researchers weren't done yet, though. After cutting the rats off from the drink, the scientists then exposed the animals to just the smell and taste of alcohol. This reminded the rodents of how much they enjoyed the drink. The scientists then scanned the rats' brains and identified the neural mechanism responsible for the reactivation of the memory of the alcohol--a molecular pathway mediated by an enzyme known as mammalian target of rapamycin complex 1 (mtORC1).

The researchers found that just a small amount of alcohol presented to the rats turned on the mTORC1 pathway specifically in a select region of the amygdala, a structure linked to emotional reactions and withdrawal from alcohol in the brain. They also found it turned on the pathway in cortical regions involved in memory processing.

After discovering this particular symptom, the researchers moved forward. They set out to see if they could prevent the reconsolidation of the memory of alcohol by inhibiting mTORC1. This would, in theory, prevent a relapse.

Using a drug called rapamycin, the researchers inactivated mTORC1. It turned out that this prevented a relapse in the rats; they didn't seek alcohol the next day. In fact, the need to drink alcohol was suppressed for 14 days with the treatment.

"One of the main problems in alcohol abuse disorders is relapse, and current treatment options are very limited," said Segev Barak, one of the researchers, in a news release. "Even after detoxification and a period of rehabilitation, 70 to 80 percent of patients will relapse in the first several years. It is really thrilling that we were able to completely erase the memory of alcohol and prevent relapse in these animals. This could be a revolution in treatment approaches for addiction, in terms of erasing unwanted memories and thereby manipulating the brain triggers that are so problematic with addictions."

The findings are published in the journal Nature Neuroscience.