Erasing Memory of Alcoholic Rats can Curb Addiction, Study Says

Researchers were able to identify and deactivate a brain pathway linked to memories that causes alcohol cravings in rats, a find that suggests that people with alcohol problems could also stay sober by erasing alcohol-associated memories that trigger relapse.

One of the main causes of relapse, according to lead author Segev Narak, is craving triggered by the memory of certain cues like walking into a bar or the smell or taste of alcohol.

"We learned that when rats were exposed to the smell or taste of alcohol, there was a small window of opportunity to target the area of the brain that reconsolidates the memory of the craving for alcohol and to weaken or even erase the memory, and thus the craving," Narak said in a statement.

In the study, which took place at the University of California - San Francisco (UCSF), researchers gave rats seven weeks to freely choose between drinking alcohol or water mixed with 20 percent alcohol. Over the time span, the rats developed a strong preference for alcohol.

Dorit Ron, a neuroscientist at UCSF, told Nature that the mixture probably tastes awful to the rats, but that they still come to drink it in large quantities.

"It's pretty amazing. You don't do anything," she said. "Over time, you can see they develop a strong preference for alcohol."

Nature reported that alcohol-binging rats reached blood alcohol contents of 80 milligrams per 100 milliliters of blood - the legal driving limit in both the United Kingdom and the United States

In the second phase, the rats were only given the opportunity to drink alcohol for one hour a day, which they learned to do by manipulating a lever. Then, the rats were put through a 10-day period of abstinence from alcohol.

Following the abstinence, the rats were exposed to just a drop of alcohol, enough of a smell and taste for them to remember how much they enjoyed drinking it. The researchers then scanned the rats' brains and identified the neural mechanism responsible for triggering the reactivation of the memory of alcohol - the mTORC1 signaling pathway.

By blocking the mTORC1 pathway, memories of past drinking episodes were disrupted.

Immediately after being exposed to the drop of alcohol, some of the rats were given a drug that inhibits mTORC1 activity. In those rats, memories of past drinking episodes were disrupted enough that researchers observed the rodents being less inclined to press a lever to receive alcohol.

According to Nature, previous work on the mTORC1 pathway suggests that disrupting it during the right timeframe can destabilize the process of memory restoration and could "potentially help treat post-traumatic stress disorder as well as drug addiction."

Charles O'Brien, director of the Center for Studies of Addiction at the University of Pennsylvania in Philadelphia, told Nature that the study was "really excellent."

"Fundamentally, addiction is a memory, and [the authors] are going straight at what is actually going on in the brain," said O'Brien, who was not involved in the study.

"I would be eager to try this in my patients as soon as it can be determined that it's safe."