Punch drunk fly love

By Emily Fasold

Humans aren’t the only ones who hit the bottle to cope with sexual frustration.

According to new research from the University of San Francisco, sex-starved male fruit flies also seek the solace of alcohol.

Authors of the study, published last month in the journal “Science”, attribute this self-medicating tendency to a brain chemical in flies called Neuropeptide F, which escalates in Volume after mating and boozing. They hypothesized that when scorned by females, fruit flies drink in order to spike levels of the chemical.

After the researchers introduced one group of flies to sexually receptive females, the mated males drank little to no alcohol provided to them through straws in the lab. However, males that failed to mate with the older, less–willing flies they were paired with drowned their sorrows in booze after the rejection.

Flies suffered through one-hour sessions of rejection three times per day, four days per week for the entirety of their two-week lives, resulting in consistently low levels of NPF.

Because humans have a similar chemical called Neuropeptide Y, researchers are hoping this discovery will give clues about how to develop pharmacological drugs to treat human addiction in the future, although no connection between the chemical and drug use has been established.

“We suspect that people may be able to look at pharmacological manipulations of Neuropeptide Y to help treat alcoholics,” said Karla Kaun, a co-author of the study.

Researchers took the experiment a step further by presenting another group of sex-craving fruit flies with dead females. Although not technically rejected by them, the male flies still drank more heavily than their sexually satisfied brethren.

“This suggested that it was lowered neuropeptide levels, and not rejection necessarily, that drives the flies to drink,” Kaun said. “We speculate that liquor is a way for them to spike the levels that would otherwise come from sex.”

Study leader Ulrike Haberlein, a professor of anatomy and neurology at the University of San Francisco, believes the study’s findings could provide significant insight into how both biology and traumatic experiences, like sexual rejection for the flies, can shape addiction.

“Ideally, I would hope that our study doesn’t just make the news because of the sexy headline but because there is potentially some treatment here for people who become alcoholics as the consequence of a traumatic event,” Haberleine said. “People who work with models of social defeat should look more closely at Neuropeptide Y levels.”

The study has received some criticism from addiction specialists. John Crum, the director of Addiction Treatment Strategies, an outpatient center in Edwardsville, Ill., does not think any valid conclusions can be drawn from the research.

“The experiment was interesting, but it’s simply too early to tell if there is a significant link between Neuropeptide Y levels and alcoholism,” Crum said. “There is not one gene or chemical that can treat addiction, a combination of environmental and genetic factors will always be needed.”

In the future, Haberlein said she and her colleagues plan to continue studying the connection between NPF, traumatic experiences and alcohol consumption in fruit flies to better understand addiction in humans.

“We think that neuropeptides are a thermostat for reward,” she said. “And we believe that it could be a major component for treating addiction in humans.”

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