Monday, 19 March 2012

Sexual Rejection leads to Alcohol Consumption in Fruit Flies


A recent study into the neuropeptide F levels (NPF) of fruit flies, Drosophila melanogaster, has shown a link between sex and alcohol consumption. The study has shown that NPF levels, believed to act as the brain’s reward system, increase after sex and decrease after sexual rejection. (Azanchi et. al 2012) Alcohol was shown to artificially increase NPF levels and alcohol consumption in sexually rejected flies was greater than that in those that had mated. (Azanchi et. al 2012) This suggests that the drop in NPF levels after rejection leads to greater alcohol consumption by the flies in order to restore normal NPF levels.

 Sex And Booze


(Barillas 2012)
The study took a control of male fruit flies and recorded the relative time spent at two different food dispensers – one mixed with 15% ethanol and another that was non-alcoholic. (Anon 2012) The flies’ neuropeptide F levels were recorded.


Female flies that have just mated will reject further suitors. (Coghlan 2012) Thus, male flies from half the control were placed in petri dishes with female flies that had not recently mated and the other half were placed with females that had recently mated. The second group which suffered rejection were shown to spend more time at the alcoholic alternative whereas the males from the first group which mated did not change their feeding pattern. (Coghlan 2012)

Neuropeptide F levels in the flies that were rejected fell by 20 to 30% while neuropeptide F levels in the flies that mated rose by a similar amount. (Coghlan 2012) This suggests that flies will consume more alcohol after rejection to restore fallen NPF levels.

In order to validate this, the researchers blocked NPF receptors in a control of male flies and placed them with female flies that had not mated. The flies mated but were found to drink as much as the flies which had been rejected due to their blocked brain receptors. (Coghlan 2012) The researchers also artificially increased NPF levels in flies which had been rejected and found that they did not change their feeding pattern. (Coghlan 2012)

 
The Drunken Fruit Fly (Alexis 2012)

This study shows a link between sexual rejection and alcohol consumption. Alcohol artificially stimulates NPF receptors which act as the brain’s reward system and was used by the male flies to restore NPF levels after rejection. (Azanchi et. al 2012) This finding is pertinent as humans have a similar peptide; neuropeptide Y. (Coghlan 2012) Neuropeptide Y has been shown to regulate anxiety. (Baxamusa 2011) It is released from the hypothalamus when the body is stressed and has a calming effect. Studies on macaques and rats show that alcohol also stimulates NPY receptors. (Coghlan 2012) This therefore highlights a relationship between NPY levels and alcohol abuse in humans. By isolating the gene which makes this peptide, scientists may modify it to control NPY levels. This would have a significant effect on people who suffer from alcoholism or drug abuse by removing the drive to use these substances.

References

Alexis, 2012, the Drunken Fruit Fly, Imagine Science Films, 18.03.12, http://imaginesciencefilms.com/2012/02/the-drunken-fruit-fly/

Anonymous, 2012, Sex-deprived fruit flies drown their sorrows with alcohol, The Sunday Times, 13.03.2012, http://www.perthnow.com.au/lifestyle/technology/male-fruit-flies-drown-their-sorrows-when-they-cant-find-a-mate/story-fn5jm47w-1226301128439

Azanchi, Kaun, Heberlein & Shohat-Ophir, 2012, Sexual Deprivation Increases Ethanol Intake in Drosophila, Science, 17.03.2012, http://www.sciencemag.org/content/335/6074/1351.abstract?sid=1ff9aef2-0555-40db-a2e7-8f7e92ff83ad

Barillas, 2012, Edge of Aging, The Cutting Edge News, 18.03.12, http://www.thecuttingedgenews.com/index.php?article=71970&pageid=28&pagename=Sci-Tech

Baxamusa, B 2011, What is Neuropeptide Y, Buzzle.com, 18.03.12, http://www.buzzle.com/articles/what-is-neuropeptide-y.html

Coghlan, A 2012, Jilted flies drown their sorrows with alcohol, Newscientist, 17.03.2012, http://www.newscientist.com/article/dn21594-jilted-flies-drown-their-sorrows-with-alcohol.html

Sexual Rejection Leads to Alcohol Consumption in Fruit Flies

Drunk as a fruit fly: A male fruit fly drinks alcohol-laced food from from a tube. (Anon 2012) 

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