Editor’s note: Every year UC Merced shines a spotlight on the cutting-edge research underway at the university. Research Week is an opportunity for the public to explore the groundbreaking work conducted by students and faculty. As part of Research Week, the Newsroom will highlight a few of these ongoing efforts. Tune in for new research stories all week long.
Humans aren’t the only species with a well-developed drinking culture. The social life of the humble fruit fly also revolves around alcohol.
Their favorite food, rotting fruit, ferments into a beer-strength quaff. Courtship often involves swarming boozy locales and getting frisky after imbibing. Flies also use alcohol as a palliative, taking to drink after repeated sexual rejection. And like humans, flies develop “drinking problems.”
Flies exposed to alcohol show behavioral changes associated with addiction. The biology behind these changes has long eluded scientists. But in a recent study published in Cell Reports, researchers at UC Merced, led by Professor Fred Wolf, identified a protein in a special kind of brain cell that’s essential to the development of alcohol tolerance and preference — key components of addiction.
“Addiction is a brain disease,” said Wolf, who's also a member of the Health Sciences Research Institute. “And we don’t have the big picture idea of what alcohol is doing in the brain.”
Wolf thinks flies might help.
Using fly brains to study addiction might seem fanciful. After all, what can they possibly tell us about our own brains? According to Wolf, a lot. That’s because flies and humans metabolize alcohol the same way. They also use the same chemicals in their brains’ reward systems.
“Flies are more like us than we’d like to believe,” Wolf said. “The structure of their brains looks very different, but when you get down to the molecular level, it’s basically the same.”
In this study, funded by the National Institutes of Health, Wolf took flies that had never been exposed to alcohol and liquored them up until they passed out. He gave them time to recover, then repeated the process.
Changes emerged after just one boozy experience. Flies needed more alcohol to reach the same level of inebriation the second time around. This is tolerance, a hallmark of addiction. Whether fly or human, frequent drinkers become desensitized to alcohol’s intoxicating effects.
But there’s more to addiction than tolerance. Preference is another defining symptom. Flies that have never imbibed shy away from alcohol. But after one exposure, they choose alcohol over alcohol-free foods.