Brain pathway could be key to new treatments
Alcohol abuse is often associated with lost memories (as in forgetting everything from how many drinks you had to how you got home after all that). But a major problem with alcoholism and other addictions is the powerful influence of past memories of drinking–these memories can easily trigger a relapse in abusive behavior. A California researcher has found that controlling memories could hold the key to treating—and preventing—alcoholism and other addictions.
In a study in Nature Neuroscience, Dorit Ron, a neuroscientist at the University of California, San Francisco, reported that, in rats at least, by blocking a signaling pathway in the brain called mTORC1, the rats were less inclined to drink alcohol. The mTORC1 pathway controls a number of proteins that appear to regulate learning and memory.
Ron started her experiment by getting the rats hooked on alcohol. When offered a choice between pure water, and water with 20 percent alcohol, the rats eventually started binging on alcohol. Their bloodstreams had alcohol levels that were equal to the legal driving limit in the United States.
Thus sated, Ron then took the alcohol away for a few days. After ten days of no drinking, she gave some rats a drop of alcohol (to trigger memories of drinking), and others the alcohol and a bit of rapamycin, which is a molecule known to disrupt the mTORC1 pathway. The rats taking the rapamycin were far less likely to want to consume more alcohol. Since it was the memory triggered by the alcohol drop that got rats drinking again, the researchers pointed to the memory disruption from rapamycin for reducing the urge to drink.
The study suggests that memory disruption can treat addictions, and possibly even post-traumatic stress disorder, by disrupting the way in which memories are retrieved and used. Rapamycin does not disrupt how memories are formed in the first place, but instead changes how the brain retrieves and responds to memories that were already formed. Therefore, the memories associated with drinking formed long ago would no longer be able to perpetuate abusive, addictive behavior. Rapamycin, which is already approved in the United States for suppressing the immune systems of people who have received transplanted organs, could possibly have a new use.
Source: Nature.com
Barak, S., Liu, F., Hamida, S., Yowell, Q., Neasta, J., Kharazia, V., Janak, P., & Ron, D. (2013). Disruption of alcohol-related memories by mTORC1 inhibition prevents relapse Nature Neuroscience DOI: 10.1038/nn.3439
