Researchers have identified the neurons of the brain responsible for alcohol cravings, and manipulated them to stop cravings in dependent rats. The research could pave the way toward drugs or gene therapy for alcohol addiction in humans, according to ScienceDaily.
The Scripps Research Institute scientists published their findings Monday in the journal Nature Communications.
“This discovery is exciting — it means we have another piece of the puzzle to explain the neural mechanism driving alcohol consumption,” said the study’s senior author, Olivier George, an associate professor at Scripps.
Using lasers, they deactivated a group of connected neurons that they had linked to alcohol cravings in earlier research. They found that both the motivation to consume alcohol, as well as the symptoms of withdrawal, subsided when they deactivated the neurons.
For several years, the team had been searching for the elements of the brain responsible for alcohol cravings. In 2016 they published findings that suggested that the driver of cravings is a particular neuronal “ensemble” of cells, called the CeA, in the central nucleus of the amygdala.
The new study examined the role of a subset of neurons within that group, called corticotropin-releasing factor (CRF) neurons. They found that these neurons account for 80 percent of the ensemble, suggesting they play a substantial role in alcohol cravings.
They targeted the neurons using optogenetics, which uses light to control cells. The researchers surgically implanted optic fibers in the rats, using light to “switch off” the CRF neurons.
In rats that had been exposed to increasingly high doses of alcohol over time, they found that the CeA ensemble became active when alcohol was made available after being taken away, suggesting it drove the motivation to drink in the addicted rats. These rats consumed even more than they had before.
But when the scientists inactivated the neurons in the alcohol-dependent rats, their consumption levels plummeted to levels in line with those before they had become dependent. And physical symptoms of withdrawal, including shaking and abnormal gait, decreased.
“In this multidisciplinary study, we were able to characterize, target and manipulate a critical subset of neurons responsible for excessive drinking,” said Scripps staff scientist, and first author of the study, Giordano de Guglielmo.
The laser treatment is not suitable for use in humans, but the information from the study could help researchers target the CRF neurons with drugs.
According to a 2017 study, alcoholism is on the rise in the US, with one in eight adults meeting the criteria for alcohol use disorder.