Vol. 5, No. 1, 1999 Page 6 
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Vol. 5, No. 1, 1999 Page 6 |
Many drinkers boast, "I can hold my liquor." Alcohol researchers know, however, that drinkers with a high tolerance for alcohol are far more likely to become alcoholics than those who feel sedated after a few drinks. But what gives these at-risk drinkers the ability to ingest more alcohol than they should?
A study by Todd Thiele and colleagues suggests that high alcohol tolerance is associated with lower levels of neuro-peptide Y, a neuromodulator known to affect eating behavior. Noting that "hard-drinking" rodents exhibit lower levels of neuropeptide Y in several brain regions than rodents who don't care much for alcohol, the researchers studied mice bred to completely lack neuropeptide Y. Thiele and colleagues say that compared to wild mice, "neuropeptide Y-deficient mice show increased consumption [of alcohol solutions and] are also less sensitive to the sedative/hypnotic effects of ethanol." In contrast, mice bred to produce excess amounts of neuropeptide Y have a lower preference for ethanol, and become sedated much more easily than other mice when t they drink alcohol.
"These data," Thiele et al. say, "are direct evidence that alcohol consumption and resistance are inversely related to neuropeptide Y levels in the brain." Thiele commented in Science News, "It's far too soon to make conclusions, [but] it's a very interesting possibility that in human alcoholics, low neuropeptide Y levels in the brain may-at least in part-contribute to alcoholism."
Because mice with low levels of neuropeptide Y exhibit increased anxiety, Thiele speculates that the mice are using alcohol to "self-medicate" and reduce their anxiety levels.
"Ethanol consumption and resistance are inversely related to neuropeptide Y levels," T. E. Thiele, D. J. Marsh, L. Ste. Marie, I. L. Benstein, and R. D. Palmiter, Nature, Vol. 396, No. 6709, November 26, 1998, pp. 366-369. Address: Todd E. Thiele, Dept. of Psychology, University of Washington, Seattle, WA 98195.