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Adolescent binge drinking disrupts gene regulation and brain development and contributes to anxiety and excessive drinking behaviors later in life, according to results from an animal study published in the journal Neurobiology of Disease.
The study, conducted by researchers from the University of Illinois at Chicago College of Medicine and supported by the National Institute of Alcohol Abuse and Alcoholism (NIAAA), which is part of the NIH, may shed some light on how drinking habits in younger years attribute to habits carried through adulthood.
Researchers modeled human binge drinking in rats by giving alcohol to the 28-day-old rats for two days on, then two days off, repeating the pattern for 13 days. The rats were followed into adulthood, where they were offered both water and alcohol, and monitored for abnormal behaviors.
Rats that were exposed to alcohol during adolescence showed changes in behavior that lasted into adulthood, including anxiety and a tendency to drink more alcohol than water. When researchers examined the amygdala of the alcohol-exposed rats, they found epigenetic changes in the complex DNA and histone proteins, including elevated levels of protein HDAC2.
The epigenetic changes were linked to lowered expression of a brain-derived neurotrophic gene and an activity-regulated cytoskeleton gene. The genes are essential for nerve cells to form new connections, resulting in diminished nerve connectivity in the amygdala of the affected adult rats.
“These findings are an important contribution to our understanding of the alcohol-induced brain changes that make alcohol problems in adulthood more likely among young people who abuse alcohol,” said NIAAA Director George F. Koob, PhD, in a news release.
When given a drug that blocks the activity of HDAC2, gene expression increased and the animals exhibited less anxiety and reduced alcohol intake.
Researchers now plan to study other epigenetic drugs to test their use in reversing the harmful brain effects of adolescent drinking.