According to a new study in animal models led by scientists at The Scripps Research Institute (TSRI), there may be a way to switch off the urge for compulsive drinking.
According to TSRI Assistant Professor Olivier George, who led the study, alcohol dependence can be completely reversed by targeting a network of neurons.
The findings which were published in the September 7 issue of The Journal of Neuroscience, built on previous studies showing that constant alcohol use can activate specific groups of neurons. Addiction and abusive use of alcohol occurs because the more a person drinks, the more they cause activation in the neuronal “circuit” which drives the use of excessive alcohol. It is as if the brain creates a special pathway between alcohol and reward.
For the new study, the researchers tried to find a way to influence only the select neurons that make these circuits. These said neurons make up only about five percent of the neurons in the brain’s central amygdala in both humans and rats.
TSRI Research Associate Giordano de Guglielmo, who was the study’s first author, spearheaded the experiment in rat models of alcohol dependence, which was designed to express a special protein to distinguish only the neurons activated by alcohol. The rats gave the researchers a new way looking into how these circuits form in human brains, where neurons that are linked to alcohol are harder to find without the use of protein labels.
The researchers later then injected the rats with a compound that could specifically deactivate neurons that are only linked to alcohol.
Among the researchers there was some surprise to see the rats completely stop their compulsive alcohol drinking, and the change lasted for as long as the rats were monitored. “We’ve never seen an effect that strong that has lasted for several weeks,” said Professor George. “I wasn’t sure if I believed it.”
The researchers ran the experiment a second and third time, and each time, the rats ceased drinking compulsively. “It’s like they forgot they were dependent,” George observed.
The researchers found out they were able to successfully target only alcohol-activated neurons, as the rats were still motivated to drink sugar water. The rats also appeared to be protected from the negative physical symptoms of alcohol withdrawal, such as shaking.
The next step the researchers are aiming for, is tracking the formation of alcohol-activated neuronal circuits over time, and to find a way to do the same work for humans. “It is very challenging to target such a small population of neurons in the brain, but this study helps to increase our knowledge of a part of the brain that is still a mystery,” said De Guglielmo.