Brain wiring of people who binge drink decoded

Washington: Scientists have found a mechanism in the brain that strongly influences how much alcohol a person is likely to consume, an advance that may lead to new drug therapies to curb excessive drinking.

It may be particularly effective among problem drinkers, half of whom are believed to have a genetically determined tendency to abuse alcohol, researchers said. "It takes them from drinking the equivalent of three to four units of alcohol in one to two hours, down to one to two," said David Rossi from Washington State University in the US.

The mechanism is found in the cerebellum, a part of the brain at the back of vertebrate skulls, in small neurons called granule cells. Sitting on the cells are proteins called GABAA receptors that act like traffic cops for electrical signals in the nervous system.

When activated, the GABAA receptor suppresses the firing of neurons, or brain circuits. Benzodiazepines, which enhance GABAA signalling, reduce this excitability, which is why they are used to treat epilepsy, researchers said.
Alcohol can also enhance GABAA receptor signalling and reduce firing in the brain, which is why it reduces anxiety and social inhibitions. In the cerebellum, it can lead to swaying, stumbling and slurred speech.

"You are inhibiting the circuit that executes normal motor function," said Rossi.
For the study, researchers injected a drug called THIP into the cerebellum of B6 mice. THIP activates the GABAA receptor, recreating the effect that alcohol has on low drinking D2 mice. It ended up deterring the B6 mice from drinking.
"The finding highlights a new region and new targets that can be manipulated to deter excessive alcohol consumption, and potentially with fewer side effects than other existing targets and brain circuits," said Rossi.

The mechanism offers a new target for drug therapies that can curb excessive drinking, researchers said. The research was published in the journal Nature Neuroscience.