Alcoholic Brains Show Key Change In Protein, Which May Flip Moderate Drinking To Problem Drinking

Binge Drinking
Researchers identify changes in the brain that lead to alcohol addiction. Photo courtesy of Shutterstock

Considering over 85 percent of people over the age of 18 report that they have drank alcohol at some point in their life, discerning who is affected by moderate drinking or problem drinking can become difficult to determine accurately. A recent study conducted at the University of California, San Francisco has revealed that microRNA, a non-coding RNA molecule that plays a major role in gene expression, may cause changes in the brain that lead to binge drinking.

"Our results suggest BDNF protects against the transition from moderate to uncontrolled drinking and alcohol use disorders," Dr. Dorit Ron, senior author of the study and a professor in UCSF's Department of Neurology, said in a statement. "When there is a breakdown in this protective pathway, however, uncontrolled excessive drinking develops, and microRNAs are a possible mechanism in this breakdown. This mechanism may be one possible explanation as to why 10 percent of the population develop alcohol use disorders, and this study may be helpful for the development of future medications to treat this devastating disease."

Ron and her colleagues examined previous studies, which found that levels of the protein brain-derived neurotrophic factor (BDNF) tend to be elevated when alcohol is consumed only in moderation. Evidence shows that higher levels of BDNF can prevent the development of alcohol use disorders. Through studies carried out on mice, the research team discovered a significant decrease in BDNF levels in the medial prefrontal cortex, the area of the brain associated with decision making.

The decline in BDNF levels was tied to an increase in the levels of a certain type of microRNA dubbed miR-30a-5p. While increasing miR-30a-5p levels reduced BDNF levels and caused mice to consume larger amounts of alcohol, treating mice with a miR-30a-5p inhibitor restored BDNF levels and returned alcohol consumption to moderate. UCSF researchers speculate that most alcohol abuse therapies fail because they decrease the experience of pleasure by inhibiting the brain’s reward pathways, while in this new study mice with a preference for alcohol had continued function in these pathways.

"In searching for potential therapies for alcohol abuse, it is important that we look for future medications that target drinking without affecting the reward system in general,” Ron added. “One problem with current alcohol abuse medications is that patients tend to stop taking them because they interfere with the sense of pleasure."

According to the National Institute on Alcohol Abuse and Alcoholism, around 17 million Americans ages 18 and over reported suffering from an alcohol use disorder in 2012 in addition to 855,000 Americans under the age of 18. Upward of 1.4 million of these Americans received treatment from a specialized facility. An estimated 88,000 people die each year as the result of an alcohol-related cause, making it the third leading preventable cause of death in the U.S.

Source: Ron D, et al. Molecular Psychiatry. 2014. 

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