Photograph by Bianca Lavies, National Geographic Stock
National Geographic News
Published December 11, 2009
After scientists had gotten them hooked on alcohol, fruit flies—apparently desperate for a buzz—drank even repulsive concoctions and relapsed after an enforced dry spell, a new study says.
Because humans and fruit flies share similar chemical pathways, the finding may shed light on the still hazy genetic roots of human alcoholism—and new ways to treat it, researchers say.
Common subjects of genetic experiments—due largely to their rapid reproduction rate—fruit flies have often been used to study intoxication and alcohol tolerance in previous experiments.
But the researchers behind the new study took aim at addiction, "so we could later work out the genes underlying addiction-like behaviors," said co-author Anita Devineni, a neuroscience graduate student at the University of California, San Francisco (UCSF).
Flies Crave Buzz?
The team presented flies with two types of liquid food, one containing ethanol, a type of alcohol. Access was unlimited, thoough the feeders were refilled only once each day.
The flies preferred the alcohol-spiked food, and the more they had it, it seems, the more they craved it—the flies' tipples grew more frequent over time.
To find out just how addicted the flies were, the researchers, in a second experiment, tainted the alcoholic food with chemicals known to repulse fruit flies—yet the flies drank on.
Flies were then forced to go cold turkey for three days—eons for a fly with a roughly monthlong life span.
As soon as the alcohol was offered again, though, the flies returned to drinking at the same extreme levels as before the dry spell, a behavior strikingly similar to that of human alcoholics relapsing after a dry period, the researchers say.
"We believe it is a behavior regulated by biological processes that may be similar in both flies and humans," said co-author Ulriki Heberlein, a UCSF biochemistry professor.
Next, the team hopes to identify the genes behind the relapses, potentially paving the way to drug treatments that could help human addicts step away from alcohol for good.
Findings appear in this week's issue of Current Biology.
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