Ten days of binge drinking disrupts neuron connections, causes anxiety and other cognitive problems

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It’s no secret that lifelong alcohol abuse is responsible for serious health problems that can lead to organ failure and diminishing cognitive function. But a recent study shows that even temporary heavy drinking can cause important cognitive impairments and problems. According to scientists in Portugal, 10 days of binge drinking can disrupt connections between neurons, leading to anxiety.

Of mice and alcohol

João Relvas, a neuroscientist at the University of Porto, and colleagues, gave male mice alcohol or water via tubes for 10 consecutive days. The rodents in the intoxicated group were given 1.5 grams of alcohol per kilogram of body weight, a dose which is equivalent to five drinks for an adult human of normal weight.

After their binge drinking streak, the mice’s brain tissue was analyzed, with the researchers finding that the heavy drinking caused microglia to destroy synapses between neurons in the prefrontal cortex.

Microglia represent a specialized population of macrophage-like cells in the central nervous system, which act as immune cells that defend the brain and spinal cord from foreign invaders. The prefrontal cortex is the part of the cerebrum that lies directly behind the eyes and the forehead. It is primarily responsible for processing complex cognition and decision making.

The synaptic dysfunction in the mice given alcohol for ten days straight led to a visible increase in anxiety-like behavior. After the researchers investigated the rodents’ brain tissue in more detail, they found that the microglia disrupted brain cells due to inflammation triggered by the alcohol.

“The loss of these connections did not cause neuronal death during the study but instead depressed neurotransmission and increased anxiety-like behaviors in the mice. These findings suggest that binge drinking induces anxiety by activating microglia that destroy neuronal connections,” the authors wrote in their study.

When the scientists blocked the production of an inflammatory molecule called TNF with pomalidomide, a commercially available drug, the synapse disruption did not occur, preventing the onset of anxiety.

Microglia from mice that were only given water (left) versus microglia in alcohol-fed mice. The panel on the right shows microglia engulfing synapses in the prefrontal cortex. Credit: Science Signaling.

These findings suggest that drugs that regulate TNF may be useful in treating alcohol addiction and the effects of alcohol abuse on the brain. This possibility would have to be investigated by clinical trials on humans.

The authors of the study also point out, however, that TNF inhibiting drugs shouldn’t be used by people who experience fallout due to a week-long heavy drinking streak. Besides cognitive impairments, binge drinking affects the whole body, negatively impacting the function of the heart, liver, pancreas, and immune system.

A 2018 study published by researchers at Vanderbilt University found that young adults who frequently binge drink have greater cardiovascular risk factors such as higher blood pressure, cholesterol and blood sugar.

Ultimately, the best treatment is prevention: only drink in moderation or don’t drink at all, the researchers cautioned.

The findings appeared in the journal Science Signaling.

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