Public Release: 

The Effects Of Alcohol In The Brain

Molecular Psychiatry

Differential Sensitivity Of c-Fos Expression In Hippocampus And Other Brain Regions To Moderate And Low Doses Of Alcohol

A.E. Ryabinin, J.R. Criado, S.J. Henriksen, F.E. Bloom, M.C. Wilson Department of Neuropharmacology, The Scripps Research Institute La Jolla, CA 92037, USA

It is known that excessive alcohol consumption can cause a number of neuropathologic and psychiatric related complications. However, the exact mechanisms underlying development of these alcohol-related disorders is unknown. Researchers using behavioral methods have suggested that the disturbing effect of alcohol on cognitive functions could be mediated by its effects on the hippocampus, a brain structure responsible for formation of complex memories and orientation in time and space. In the present study, scientists from The Scripps Research Institute (La Jolla, California, USA) have traced the levels of the protein c-Fos, which provides a general index of activity of neurons in the brain. In rats that have been given intoxicating amounts of alcohol (corresponding to three-four drinks in humans) the level of this protein was stimulated in several regions of the brain, particularly those parts involved in regulating emotions and behavioral motivation, and in processing sensory stimulation. In contrast, the level of this protein was selectively decreased only in the hippocampus. This moderate dose of alcohol did not only decrease the levels of c-Fos protein in the hippocampus of otherwise untreated rats, but it also blocked the increased activity which typically occurs when the animal is exposed to a novel environment. This blockade indicates that alcohol perturbs the normal experience-mediated activation of the hippocampus, which may explain alcohol's effects in suppressing the ability to remember novel information. A lower dose of alcohol (corresponding to one-two drinks) also decreased levels of c-Fos in otherwise untreated rats, but was unable to block the response in hippocampus of animals exposed to a novel environment. This suggests that this lower dose is not enough to perturb the processing of new information in the hippocampus. In summary, these studies lay ground for understanding the mechanisms by which excessive alcohol drinking can disturb cognitive functions. Taken together with behavioral studies, these results help explain why after recovering from an alcohol intoxication one may not remember specific experiences or the place where drinking occurred due to the disruption of hippocampal function, but still have a feeling that a good (or bad) time was had due to spared functions of other brain structures. An independent commentary by J. C. Crabbe will be published in the same issue of Molecular Psychiatry. Dr. Crabbe is at the Portland Alcohol Research Center, Portland Oregon, e-mail:

This article will be published in the January 1997 issue of Molecular Psychiatry, an independent peer-reviewed journal published by Stockton Press/Macmillan Press. Editorial decisions and publication in Molecular Psychiatry do not constitute endorsement by the National Institute of Mental Health, the National Institutes of Health, or by any branch of the United States government.

Editor: Julio Licinio, MD - editorial assistant: Rachel Lisman
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Publisher: Marija Vukovojac, Stockton Press,
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For information on the scientific aspects of the article please contact the author:
Andrey Ryabinin, Ph.D., Department of Neuropharmacology,
The Scripps Research Institute
10666 North Torrey Pines Rd., La Jolla, CA 92037, USA
Tel:619-784-7176; Fax: 619-784-7377;


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