Scientists were able to suppress memories that caused alcohol cravings in rats by deactivating a brain pathway.
The Ernest Gallo Clinic and Research Center at UC San Francisco study found a way to stop addicted rats from drinking alcohol, according to a press release.
"One of the main causes of relapse is craving, triggered by the memory by certain cues - like going into a bar, or the smell or taste of alcohol," said Segev Barak, PhD, the lead author of the study. "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."
The study allowed rats to choose between water and alcohol over a seven-week period, towards the end of the experiment the rats had developed a strong preference for the alcoholic beverages.
After the seven weeks were up the rats were only allowed to have alcohol for one hour a day, and needed to activate a lever in order to access it, they then went 10 days without any alcohol at all.
During the rat's "dry" period they were exposed to stimuli that reminded them of how much they liked alcohol, such as smells. The researchers scanned the animal's brains and were able to isolate the neural mechanism which caused the alcohol cravings. They named the enzyme present in the molecular pathway rapamycin complex 1 (mTORC1).
Researchers observed even a small drop of alcohol would release the enzyme in the area of the brain known as the amygdala, responsible for emotional reactions to alcohol withdrawal, and the cortical region which controls memory triggers. Once mTORC1 was released in the rat's brain they had a relapse, and began to press the lever in hopes of getting some alcohol.
"The smell and taste of alcohol were such strong cues that we could target the memory specifically without impacting other memories, such as a craving for sugar," Barak said.
After discovering what caused the memory-triggered cravings, the team set out to find a cure. The researchers administered a drug called rapamycin directly after the rats were exposed to the triggers, the next day the rats showed no relapse.
In the future, the team hopes to carry this new research over to people struggling with addiction.
"One of the main problems in alcohol abuse disorders is relapse, and current treatment options are very limited." Barak said. "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 for people with addictions."
