This protein regulates nerve-cell adhesion and movement, processes critical to getting the cells to their proper position in a developing brain. Charness and his colleagues gave specific nerve cells growing in laboratory cultures alcohol concentrations equivalent to those resulting when a woman has one to two drinks. This alcohol can prevent nerve cells guided by L1 from adhering to each other, Charness says. In a pregnant woman, this effect may interfere with the fetus's developmental steps, he says. Whether these changes would be significant enough to disrupt brain function in people or animals, however, is still unknown.
Ethanol is the alcohol in beer, wine, and other drinks.
In experiments reported in the March 28 Proceedings of the National Academy of Sciences , Charness and his colleagues found that some other forms of alcohol, such as octanol, can block ethanol's action. Their results suggest that ethanol targets a specific area on L1, Charness says. Besides encouraging cell adhesion, L1 can trigger nerve cells to grow toward each other and form connections. Ethanol concentrations mimicking a woman's exposure to a single glass of wine seem to slow the growth of such connections, reports Cynthia F. Bearer of Case Western Reserve University School of Medicine in Cleveland. Other researchers have found that genetic mutations in L1 result in damage to the corpus callosum, the bundle of fibers that connects the brain's two sides, Charness says.