(Embargoed) CHAPEL HILL Although scientists have known for years that cocaine, marijuana and heroin interact with specific proteins in the brain, traditionally they have thought alcohol had no such pointed effects.
Now University of North Carolina at Chapel Hill researchers have found evidence that alcohol inhibits the actions of key proteins called N-methyl-D-aspartic acid (NMDA) receptors in specific regions of the brain.
A report on their work appears Thursday (Nov. 15) in the November issue of the journal Alcoholism: Clinical & Experimental Research.
NMDA receptors in the brain are key sites of action of the neurotransmitter glutamate, which increases the activity of brain neurons, said lead author Dr. Darin J. Knapp, research assistant professor of psychiatry at the UNC School of Medicine. Earlier investigations have shown that alcohol-NMDA interactions influence many features of alcohol exposure, including effects on fetal development, seizures, gene expression in brain, intoxication, tolerance to ethanol and alcohol dependence.
Conducted on rats, the new study sought to induce and block Fos protein in brain as measured with Fos-like Immunohistochemistry (Fos-LI), Knapp said. Fos proteins belong to a family of proteins known to reflect changes in cellular activity and participate in regulating gene activity.
Measurement of Fos-LI is a form of brain mapping that allows researchers to identify and note brain regions that change their activity after different challenges, such as alcohol consumption, he said.
Researchers gave rats NMDA or alcohol by various routes to determine brain responses.
Alcohols main effect was to inhibit or prevent NMDA-induced Fos protein induction, Knapp said. That means Fos protein induction by NMDA -- and the blockage caused by alcohol -- occurred in specific brain regions such as the prefrontal cortex and hippocampus, which are key to memory formation and hi
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Contact: David Williamson
david_williamson@unc.edu
919-962-8596
University of North Carolina at Chapel Hill
14-Nov-2001