Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Starvation Keeps Sleep-Deprived Fly Brain Sharp

01.09.2010
As anyone who has ever struggled to keep his or her eyes open after a big meal knows, eating can induce sleepiness. New research in fruit flies suggests that, conversely, being hungry may provide a way to stay awake without feeling groggy or mentally challenged.

Scientists at Washington University in St. Louis found that starvation allows the need for nourishment to push aside the need for sleep. Like humans and rats, fruit flies cannot survive without sleep. But in a line of flies engineered to be sensitive to sleep deprivation, starvation nearly tripled the amount of time they could survive without sleep.

Researchers showed that the ability to resist the effects of sleep loss was linked to a protein that helps the fruit fly brain manage its storage and use of lipids, a class of molecules that includes fats such as cholesterol and fat-soluble vitamins such as vitamins A and D.

"The major drugs we have to either put people to sleep or keep them awake are all targeted to a small number of pathways in the brain, all of them having to do with neurotransmission," says Paul Shaw, PhD, assistant professor of neurobiology and anatomy. "Modifying lipid processing with drugs may provide us with a new way of tackling sleep problems that is more effective or has fewer side effects."

The study appears online Aug. 31 in PLoS Biology.

The findings add a new wrinkle to the complex relationship between sleep and dietary metabolism. Scientists recognized about a decade ago that inadequate sleep results in obesity and contributes to the development of diabetes and coronary disease. Until now, no one had connected genes linked to lipids with regulation of the need for sleep.

Clay Semenkovich, MD, a Washington University lipid expert not directly involved in the study, says the results fit into a growing awareness that organisms use lipids for much more than energy storage.

"It's becoming apparent that fats serve as signaling molecules in a number of contexts," says Semenkovich, the Herbert S. Gasser Professor of Medicine. "If you identify the appropriate lipids involved in sleep regulation and figure out how to control them, you may be able to decrease suffering associated with loss of sleep or the need to stay awake."

Shaw uses fruit flies as models for sleep's effects in higher organisms. He was among the first to prove that flies enter a state comparable to sleep, showing that they have periods of inactivity where greater stimulation is required to rouse them. Like humans, flies deprived of sleep one day will try to make up for it by sleeping more the next day, a phenomenon referred to as sleep debt. Sleep-deprived flies also perform poorly on a simple test of learning ability.

Studies in other labs have shown that starvation or, in the case of human volunteers, fasting leads to less sleep. More recent research has also shown that starvation can change the activity levels of genes that manage storage and use of lipids.

Shaw's lab previously demonstrated that fruit flies with a mutation in a timekeeping gene accumulate sleep debt much more quickly and begin dying after being kept awake for as little as 10 hours. Matt Thimgan, PhD, a postdoctoral research associate, reports in the new paper that starving fruit flies spent more time awake, and starving fruit flies with the timekeeping gene mutation could survive up to 28 hours without sleep.

Scientists tested the starving, sleepless flies for two markers of sleep debt: an enzyme in saliva and the flies' ability to learn to associate a light with an unpleasant stimulus. Both tests showed that the starving flies were not getting sleepy.

"From an evolutionary perspective, this makes sense," Thimgan says. "If you're starving, you want to make sure you're on the top of your game cognitively, to improve your chances of finding food rather than becoming food for someone else."

Scientists found an effect similar to starvation in fruit flies where a gene called Lipid storage droplet 2 (LSD2) was disabled. After sleep deprivation, flies with the LSD2 mutation were less likely to sleep for longer periods of time and continued to score high on the learning test.

"LSD2 mutants seem to constantly rotate lipids through their storage depot in cells, putting them in and moving them out very quickly," Thimgan says. "Disabling LSD2 appears to make it hard for cells to hold on to lipids and use them properly, and we think this impairs brain cells' ability to respond to sleep deprivation."

Researchers are working to identify the specific lipids affected by loss of LSD2.

Thimgan MS, Suzuki Y, Seugnet L, Gottschalk L, Shaw PJ. The Perilipin homologue, Lipid storage droplet 2, regulates sleep homeostasis and prevents learning impairments following sleep loss. PLoS Biology, Aug. 31, 2010.

Funding from the National Institutes of Health and the WM Keck Foundation supported this research.

Washington University School of Medicine's 2,100 employed and volunteer faculty physicians also are the medical staff of Barnes-Jewish and St. Louis Children's hospitals. The School of Medicine is one of the leading medical research, teaching and patient care institutions in the nation, currently ranked fourth in the nation by U.S. News & World Report. Through its affiliations with Barnes-Jewish and St. Louis Children's hospitals, the School of Medicine is linked to BJC HealthCare.

Michael C. Purdy | Newswise Science News
Further information:
http://www.wustl.edu

More articles from Life Sciences:

nachricht Antimicrobial substances identified in Komodo dragon blood
23.02.2017 | American Chemical Society

nachricht New Mechanisms of Gene Inactivation may prevent Aging and Cancer
23.02.2017 | Leibniz-Institut für Alternsforschung - Fritz-Lipmann-Institut e.V. (FLI)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

From rocks in Colorado, evidence of a 'chaotic solar system'

23.02.2017 | Physics and Astronomy

'Quartz' crystals at the Earth's core power its magnetic field

23.02.2017 | Earth Sciences

Antimicrobial substances identified in Komodo dragon blood

23.02.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>