Scientists Locate Neurons in Brain Responsible for Alcoholism

By May Wilkerson 09/08/15

Doctors may soon be able to predict if an individual will be a compulsive drinker.

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Your doctor may soon be able to figure out if you’re an alcoholic just by looking at your brain.

Researchers at Texas A&M College of Medicine have identified a population of neurons in the brain that influences whether one drink leads to two and could predict if a person is likely to drink compulsively.

The study, published in the Journal of Neuroscience, found that alcohol consumption actually changes the structure and function of neurons in the dorsomedial striatum, a part of the brain known to be important in goal-driven behaviors. Scientists say the findings could be a first step towards developing a cure for alcoholism and other addictive behaviors.

Despite being a widespread problem, little is known about alcoholism and what causes it, said study lead author Jun Wang, M.D., Ph.D., from the Department of Neuroscience and Experimental Therapeutics at Texas A&M.

Using an animal model, Wang and his colleagues determined that alcohol actually changes the physical structure of medium spiny neurons, the main type of cell in the striatum. These neurons are “spiny” because they have many branches, like a tree, each with tiny “spines” coming off them. Each “spine” has one of two types of dopamine receptors, D1 or D2. D1 receptors (or “neurons”) are like green lights, telling you to “go” while D2 receptors are like red lights, saying “stop” or “do nothing.”

It was already known that the neurotransmitter dopamine is involved in addiction. This study goes a step further, showing that the dopamine D1 receptor in particular plays an important role in addiction. The team found that consumption of large amounts of alcohol makes D1 neurons more excitable, which means that they activate more easily with less stimulation. “If these neurons are excited, you will want to drink alcohol,” said Wang. “You’ll have a craving.”

So when neurons with D1 receptors are activated, they compel you to “go” or act; in this case, reaching for a second drink, or a third, or fourth, etc. This creates a cycle, where drinking leads to more drinking. “When you drink alcohol, long-term memory is enhanced, in a way,” said Wang. “But this memory process is not useful—in fact, it underlies addiction since it affects the ‘go’ neurons.”

The animal models with increased D1 neurons also had more of a preference to drink large quantities of alcohol when given the opportunity. “Even though they’re small, D1 receptors are essential for alcohol consumption,” said Wang. This means scientists may be able to predict a person’s predilection towards alcoholism by examining this region of the brain.

Even more importantly, when these same animal models were given a drug to at least partially block the D1 receptor, they were much less likely to desire alcohol. These findings could be used to help develop drugs to block cravings in humans.

“If we suppress this activity, we’re able to suppress alcohol consumption,” said Wang. “This is the major finding. Perhaps in the future, researchers can use these findings to develop a specific treatment targeting these neurons.”

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May Wilkerson is a writer, comic and Managing Editor @someecards. Co-host of the podcast Crazy; In Bed w/alyssalimp. She is also the top Google result for "insufferable lunatic." Follow this insufferable lunatic on Twitter.