The UNC findings, from research at UNC's Bowles Center for Alcohol Studies, were based on an animal model of chronic alcohol dependence, in which adult rats were given alcohol over four days in amounts that produced alcohol dependency. The study is in the Oct. 27 issue of the Journal of Neuroscience.
In 2002, Dr. Fulton T. Crews, Bowles Center director, and Bowles Center research associate Dr. Kim Nixon were the first to report that alcohol, during intoxication, has a detrimental effect on the formation of new neurons in the adult rat hippocampus. This brain region is important for learning and memory - in animals and humans - and is linked to psychiatric disorders, particularly depression.
"When used in excess, alcohol damages brain structure and function. Alcoholics have impairments in the ability to reason, plan or remember," said Crews, also professor of pharmacology and psychiatry in UNC's School of Medicine. "A variety of psychological tests show alcoholics have a difficulty in ability to understand negative consequences."
In the new study, senior co-author Crews and co-author Nixon found inhibition of neurogenesis, or brain cell development, during alcohol dependency, followed by a pronounced increase in new neuron formation in the hippocampus within four-to-five weeks of abstinence. This included a twofold burst in brain cell proliferation at day seven of abstinence.
"We looked at dividing cells after our four-day binge model of alcohol dependency and confirmed what we previously observed: When the animals were intoxicated, the measure of dividing cells decreases," said Nixon. "And after abstinence for one week, we saw a huge burst in the number of new cells being born."
Nixon said the findings were confirmed by use of several biologic
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Contact: L.H. Lang
llang@med.unc.edu
919-843-9687
University of North Carolina School of Medicine
5-Nov-2004