Fruit flies too can suffer from alcohol addiction.
SYDNEY: Given the chance, fruit flies will consume alcohol until they are intoxicated and enjoy it more and more over time, much like a human alcoholic, a new study has found.
In the study, published in the journal Current Biology, the fruit flies were given a choice between food containing 15% ethanol, and regular, ethanol-free food over a five-day period.
The flies not only displayed an obvious preference for the ethanol-laced food, they consumed it with increased frequency over time. They continued to do so even when the food was laced with bitter and unpalatable quinine. They couldn’t get enough, it seemed.
"The new findings are a substantial step forward in validating a Drosophila [fruit fly] model for the study of alcohol addiction," said Ulrike Heberlein, a molecular geneticist from the University of California at San Francisco, who co-authored the study.
"Because of the wealth of tools available in Drosophila, together with the ease and speed with which they can be manipulated genetically, this new paradigm provides a foundation to begin finding the genes that contribute to alcohol addiction," she said.
Researchers established that neither caloric nor sensory attraction to ethanol could entirely account for the fruit flies’ preference. For example, while flies are attracted to the smell of ethanol, they don’t like the taste.
However, fruit flies manipulated to have no taste receptors displayed no difference in ethanol preference to the control flies, suggesting that the fact they find ethanol unpalatable did not affect their choice.
According to the study, this use of alcohol despite 'averse consequences' (ie. the taste) is a key feature of alcohol addiction.
Another behavioural characteristic of alcoholism is 'relapse' - that is, a return to an equal or greater consumption of alcohol following a prolonged period of abstinence - a behaviour that was also found in the fruit flies.
Mark Daglish, an addiction psychiatrist from the University of Queensland, in Brisbane, said the findings could eventually lead to improved treatments for alcoholism in humans.
"It's always difficult to look at the more subtle social aspects of alcohol dependence, such as craving and peer pressure,” he said, “but if this can give us some clues as to whether response to treatment could also be genetically mediated, then it would definitely be useful."
