Posted on 03/15/2012 1:22:12 PM PDT by Red Badger
Sexually deprived male fruit flies exhibit a pattern of behavior that seems ripped from the pages of a sad-sack Raymond Carver story: when female fruit flies reject their sexual advances, the males are driven to excessive alcohol consumption, drinking far more than comparable, sexually satisfied male flies.
Now a group of scientists at the University of California, San Francisco (UCSF) has discovered that a tiny molecule in the fly's brain called neuropeptide F governs this behavior—as the levels of the molecule change in their brains, the flies' behavior changes as well.
The new work may help shed light on the brain mechanisms that make social interaction rewarding for animals and those that underlie human addiction. A similar human molecule, called neuropeptide Y, may likewise connect social triggers to behaviors like excessive drinking and drug abuse. Adjusting the levels of neuropeptide Y in people may alter their addictive behavior—which is exactly what the UCSF team observed in the fruit flies.
"If neuropeptide Y turns out to be the transducer between the state of the psyche and the drive to abuse alcohol and drugs, one could develop therapies to inhibit neuropeptide Y receptors," said Ulrike Heberlein, PhD, a Professor of Anatomy and Neurology at UCSF, who led the research.
Clinical trials are underway, she added, to test whether delivery of neuropeptide Y can alleviate anxiety and other mood disorders as well as obesity.
A Reward Switch in the Brain
The experiments, described this week in the journal Science, started with male fruit flies placed in a container with either virgin female flies or female flies that had already mated. While virgin females readily mate and are receptive toward courting males, once they have mated, females flies lose their interest in sex for a time because of the influence of a substance known as sex peptide, which males inject along with sperm at the culmination of the encounter. This causes them to reject the advances of the male flies.
The rejected males then gave up trying to mate altogether. Even when placed in the same cage as virgin flies, they were not as keen to have sex. Their drinking behavior also changed.
When placed by themselves in a new container and presented with two straws, one containing plain food and the other containing food supplemented with 15 percent alcohol, the sexually rejected flies binged on the alcohol, drinking far more than their sexually satisfied cousins whose advances were never spurned. The difference was not only apparent in their behavior. It was completely predicted by the levels of neuropeptide F in their brains.
"It's a switch that represents the level of reward in the brain and translates it into reward-seeking behavior," said Galit Shohat-Ophir, PhD, the first author of the new study.
A former postdoctoral researcher at UCSF, Shohat-Ophir is now a research specialist at the Howard Hughes Medical Institute (HHMI) Janelia Farm Research Center in Ashburn, VA. Later this year, Heberlein will also move to Janelia Farm, where she will become scientific program director.
Experiments Began as a "Crazy" Idea
When the work first started a few years ago, Shohat-Ophir said, it was just a crazy idea. The UCSF team suspected there might be a molecular mechanism in the brain linking social experiences like sexual rejection to psychological states such as depression of the brain system that responds to rewards. So they decided to test whether flies that were rejected sexually would be more prone to drinking.
Flies in the laboratory will normally drink to intoxication if given the choice, but this behavior is altered when neuropeptide F levels are altered in their brains because of their sexual experiences. Mated flies are less likely to seek out such rewarding experiences.
The male flies that were paired with receptive virgin females from the start and successfully mated had lots of neuropeptide F in their brains and drank very little alcohol.
Rejected flies, on the other hand, had lower levels of neuropeptide F in their brains, and sought alternative rewards by drinking to intoxication.
In their work, Heberlein, Shohat-Ophir, and their colleagues showed that they could induce the same behaviors by genetically manipulating the neuropeptide F levels in the flies' brains. Activating the production of neuropeptide F in the brains of virgin males flies made them act as if they were sexually satisfied, and they voluntarily curtailed their drinking.
Lowering the levels of the neuropeptide F receptor made flies that were completely sexually satisfied act as if they were rejected, inciting them to drink more.
The finding has great relevance to addressing human addiction, though it may take years to translate this discovery into any new therapies for addicts, given the much greater complexities of the human mind.
The human version of neuropeptide F, called neuropeptide Y, may work similarly, connecting socially rewarding experiences to behaviors like binge drinking. Already, scientists know that levels of neuropeptide Y are reduced in people who suffer from depression and post-traumatic stress disorder—conditions that are also known to predispose people toward excessive alcohol and drug abuse.
Manipulating neuropeptide Y may not be so straightforward, however, since the molecule is distributed all over the human brain—and based on rodent studies, it has roles in feeding, anxiety and sleep, in addition to alcohol consumption.
More information: The article, "Sexual Deprivation Increases Ethanol Intake in Drosophila" by Shohat-Ophir, K. R. Kaun, R. Azanchi and U. Heberlein appears in the March 16 issue of the journal Science: http://www.sciencemag.org
:: a tiny molecule in the [fruit] fly’s brain ::
When I read this, I’m thinking the about the totality of liberal thought and brain-power.
This explains my college experience.
So if my wife wants me to stop drinking....
ROFLMAO!!!!............EXCELLENT!..........I NOMINATE THAT FOR POST OF THE DAY!!!!......................
Everybody must believe in something.......I believe I'll have another drink...............
Do you know what moth balls smell like?...........
I have to wonder if chimpanzees have more class.
Anyone surprised that a study like this came from the SF Bay Area? Those people are sex addled.
I am sure glad my tax dollars which the government takes are giving grants to universities to study stupid theories like this. What a scam which is being repeated time after time in our institutes of higher learning.
Well, they are fruits.........
They think they find a link to drinking in the fruit fly and they are already braying about applying it to humans. But somehow, we need human aborted baby stem cells NOW to test thing they never talk about trying in animals. Does this smell bogus to you?
I'm thinking that behaviors have the same effect on brain chemistry...
It all makes sense when you understand where they’re coming from.
Take God’s truth, turn it upside down, and you’ll have, 99% of the time, the leftist viewpoint on any issue.
Unfortunately, rehab is probably in your future. ;-)
Sorry, but I’ve seen people “become” addicted to substances. It wasn’t due to a lack of will power. It wasn’t laziness. And it wasn’t weakness. My mother is addicted to pain medication. This occured from years of being on pain medications to address both the multiple back and neck surgeries she has had, as well as having Lupis. Her back and neck injuries were not caused by laziness, or weakness. Her Lupis was not the result of a lack of will power.
just about every bender I went on as a single guy was;
one: in search of poozay
and
two: the only thing left to do after striking out.
Hell ... 'learned THAT jit at the age of 17 !
Not to mention the constant threat of genocide from the 'giants'. It isn't at all unusual for a poor fruit fly to be out eating with his friends, and suddenly the giants send out canisters of toxic gas that kills hundreds, if not thousands of them at a time. As a fruit fly, you just know that any given meal could very well be your last.
Not the same. There’s no chemical reward/alteration going on with someone just doing the same chore every day. I don’t have to drive home from work every day at the exact same time, or have to go the same way, or at the same speed or faster, etc. Doing chores don’t make me obsess about doing the chore again. Or wanting to do it again. Washing dishes? Even something like eating a big dinner doesn’t make me want to sit around thinking about eating a big dinner again, or when’s the next time I can score a big dinner again. Or steal food from my neighbor because I don’t have any food left in the house.
I really have to disagree. Again this is not excusing them of their addiction or their responsibilities. If it were what you say then everyone’s addicted because any behavior we do normally could be classified as such, it’s such a massively broad definition. Behaviors you can stop or start, or change, and not have it bother you. Addicts cannot do that. Their body is chemically addicted to certain substances. That’s why they do things that appear insane and irrational to non drug-addict people.
I don't know... does that make you smarter than a fruit-fly? ;-)
I fired an employee Tuesday after I walked around a corner and caught him taking a hit off a tiny little pipe while standing at his machine, I was quiet and he didn’t hear me coming. I couldn’t believe how STUPID he was to sit there smoking Spice at 11:20 in the morning on my shop floor, I have to say I damn near lost it.
Addiction must be hard for someone who has never gone through it to understand I guess, he threw away a perfectly good job he was happy with because he had to have his “fix”. (I say that calmly now after I had time to think about it. I peeled the paint off the walls while escorting him out of my shop at the time though.)
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