"Our animal studies indicate that significant nerve cell death occurs in the infant mouse brain following exposure to blood alcohol levels equivalent to those a human fetus would be exposed to by maternal ingestion of two cocktails," says investigator John W. Olney, M.D., the John P. Feighner Professor of Neuropsychopharmacology at Washington University School of Medicine in St. Louis. "With anesthetic drugs, a dose required to lightly anesthetize an infant mouse for about one hour is sufficient to trigger nerve cell death."
For several years, Olney's research has suggested that exposure to alcohol and anesthetic drugs can cause developing brain cells to undergo neuroapoptosis -- brain cell suicide -- but in those previous studies, he was observing damage when laboratory animals were exposed to large amounts of the drugs.
In the most recent studies, alcohol was administered on a one-time basis to infant mice in doses required to produce various blood alcohol levels. When the animals' brains were examined six hours later, the researchers found that blood alcohol elevation in the range of 0.07 percent, lasting for one hour, was sufficient to cause more nerve cell death than in mice not receiving alcohol. The minimum legal blood alcohol concentration for driving in most states is between 0.08 and 0.10 percent.
"Assessing the significance of these findings is complicated by the fact that brain cell suicide occurs naturally at a low rate during development," Olney says. "Transient exposure to small amounts of alcohol or an anesthetic drug causes a two- to four-fold increase in the rate of brain cell suicide. Although more nerve cells die than would have died naturally during
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Contact: Jim Dryden
jdryden@wustl.edu
314-286-0110
Washington University School of Medicine
13-Feb-2004