Nav: Home

Can't sleep? Fruit flies and energy drinks offer new clues

November 08, 2018

Sleep is an essential behavioral state in animals ranging from invertebrates to humans. It is critical for immune function, stable metabolism, brain repair, learning and memory. Over the course of a lifetime, more than 30 percent of people will experience a sleep disorder, which is associated with a number of diseases including Alzheimer's, type 2 diabetes, and cardiovascular disease.

There is growing evidence that glial cells (or glia), long thought to simply "support" neurons within the brain, are actually quite important for diverse aspects of sleep regulation. Thanks to Drosophila melanogaster (more affectionately known as the fruit fly), research teams at Florida Atlantic University and McGill University in Quebec have discovered a new mechanism regulating sleep that involves glia and their ability to manage a common ingredient found in many energy drinks like Red Bull™.

Fruit flies share 75 percent of the genes that cause diseases in humans and display all of the behavioral and physiological characteristics of sleep. For the study, published in the journal Current Biology, the researchers sought to identify new genes affecting sleep and wakefulness in fruit flies. With this approach, they uncovered a gene that encodes the membrane transport protein known as excitatory amino acid transporter 2 or Eaat2.

They found that Eaat2 promotes wakefulness in fruit flies by limiting the length and intensity of sleep periods. They also discovered that it does this by controlling the movement of taurine - the ingredient found in many energy drinks - into glial cells of the fly brain. In humans, taurine is consistently elevated in blood and urine of sleep-deprived people, but it is unknown if taurine levels also change in the brain after sleep deprivation.

Like humans, fruit flies are highly active during the day and sleep throughout the night. The authors found that disruption of Eaat2 in fruit flies caused excess daytime sleepiness.

"Daytime sleep is more fragmented than nighttime sleep, and disrupting Eaat2 function led to daytime sleep that mimics sleep typically observed only during the night," said Bethany A. Stahl, Ph.D., a lead author on the study and a post-doctoral fellow in the lab of Alex C. Keene, Ph.D., an associate professor of biological sciences in FAU's Charles E. Schmidt College of Science and a member of the Jupiter Life Science Initiative (JSLI).

"About 70 million Americans suffer from sleep disorders, and we believe that raising awareness of the importance of understanding fundamental mechanisms of sleep is an important issue globally," said Keene.

To determine the role of Eaat2 in metabolic regulation, the researchers simultaneously measured sleep and CO? output from single flies.

"We think the identification of Eaat2 as a modulator of sleep will be important for researchers who study sleep regulation, sleep-dependent changes in metabolism, and perhaps physicians treating patients with sleep disorders," said Keene. "It suggests sleep researchers need to look beyond the role of neurons to examine how glial cells control our sleep-wake regulation."

The team found that Eaat2 works in specific glial cells of the fly brain, rather than in neurons.

"Our research adds wakefulness to the growing list of fruit fly behaviors where glial cells play an important regulatory role, which includes circadian rhythms, movement, courtship, learning and memory," said Emilie Peco, Ph.D., who co-led the study and is a research associate in the lab of Don van Meyel, Ph.D., a professor of neurology at the McGill Centre for Research in Neuroscience, and the BRaIN Program of the Research Institute of the McGill University Health Centre.

Eaat2 was previously shown to transport taurine. So to test if taurine might explain how Eaat2 affects sleep, Stahl fed taurine to some flies and found they slept more during the daytime than the control flies, but only if Eaat2 was present.

"The study led by Dr. Stahl and Dr. Peco focuses on fundamental mechanisms of sleep and glial cells in flies, but we expect our discovery will fuel research to determine if a mechanism involving the transport of taurine to and from glial cells might influence sleep in humans," said van Meyel. "Even if you don't indulge in energy drinks, there is a lot of taurine in the human brain, and what it does there is not understood all that well."
-end-
Study co-authors are Sejal Davla, Ph.D., McGill University; and Kazuma Murakami, Ph.D., and Nicholàs A. Caicedo Moreno, Ph.D., both at FAU. The collaboration between the teams at FAU and McGill developed organically from the Keene lab's focus on sleep research and the van Meyel lab's expertise in glial cells and membrane transport proteins.

This work was supported by the National Institutes of Health (NIH), the Canadian Institutes of Health Research (CIHR), the Natural Sciences and Engineering Research Council of Canada, and the Canada Foundation for Innovation.

JLSI is aimed at building educational and research capabilities in the life sciences on FAU's John D. MacArthur Campus in Jupiter, and is a collaborative effort between the Charles E. Schmidt College of Science and the Harriet L. Wilkes Honors College.

About Florida Atlantic University:

Florida Atlantic University, established in 1961, officially opened its doors in 1964 as the fifth public university in Florida. Today, the University, with an annual economic impact of $6.3 billion, serves more than 30,000 undergraduate and graduate students at sites throughout its six-county service region in southeast Florida. FAU's world-class teaching and research faculty serves students through 10 colleges: the Dorothy F. Schmidt College of Arts and Letters, the College of Business, the College for Design and Social Inquiry, the College of Education, the College of Engineering and Computer Science, the Graduate College, the Harriet L. Wilkes Honors College, the Charles E. Schmidt College of Medicine, the Christine E. Lynn College of Nursing and the Charles E. Schmidt College of Science. FAU is ranked as a High Research Activity institution by the Carnegie Foundation for the Advancement of Teaching. The University is placing special focus on the rapid development of critical areas that form the basis of its strategic plan: Healthy aging, biotech, coastal and marine issues, neuroscience, regenerative medicine, informatics, lifespan and the environment. These areas provide opportunities for faculty and students to build upon FAU's existing strengths in research and scholarship. For more information, visit http://www.fau.edu.

Florida Atlantic University

Related Sleep Articles:

Baby sleeping in same room associated with less sleep, unsafe sleep habits
The American Academy of Pediatrics (AAP) recommends parents keep babies in the same room with them to sleep for the first year to prevent sudden infant death syndrome (SIDS).
Alternating skimpy sleep with sleep marathons hurts attention, creativity in young adults
Skimping on sleep, followed by 'catch-up' days with long snoozes, is tied to worse cognition -- both in attention and creativity -- in young adults, in particular those tackling major projects, Baylor University researchers have found.
Sleep trackers can prompt sleep problems
A researcher and clinician in the sleep disorders program in the Department of Behavioral Sciences at Rush University Medical Center and an associate professor at Rush University, Baron says use of these devices follows a pattern reflected in the title of the Sleep Medicine study: 'Orthosomnia: Are Some Patients Taking the Quantified Self Too Far?'
UW sleep research high-resolution images show how the brain resets during sleep
Striking electron microscope pictures from inside the brains of mice suggest what happens in our own brain every day: Our synapses -- the junctions between nerve cells -- grow strong and large during the stimulation of daytime, then shrink by nearly 20 percent while we sleep, creating room for more growth and learning the next day.
What is good quality sleep? National Sleep Foundation provides guidance
The National Sleep Foundation (NSF) recently released the key indicators of good sleep quality, as established by a panel of experts.
Homeless sleep less, more likely to have insomnia; sleep improvements needed
The homeless sleep less and are more likely to have insomnia and daytime fatigue than people in the general population, findings researchers believe suggest more attention needs to be paid to improving sleep for this vulnerable population, according to a research letter published online by JAMA Internal Medicine.
Losing sleep over discrimination? 'Everyday discrimination' may contribute to sleep problems
People who perceive more discrimination in daily life have higher rates of sleep problems, based on both subjective and objective measures, reports a study in Psychosomatic Medicine: Journal of Biobehavioral Medicine, the official journal of the American Psychosomatic Society.
Mouse mutants with sleep defects may shed light on the mysteries of sleep
The first unbiased genetic screen for sleep defects in mice has yielded two interesting mutants, Sleepy, which sleeps excessively, and Dreamless, which lacks rapid eye movement (REM) sleep.
Brain circuit that drives sleep-wake states, sleep-preparation behavior is identified
Stanford University School of Medicine scientists have identified a brain circuit that's indispensable to the sleep-wake cycle.
Recharge with sleep: Pediatric sleep recommendations promoting optimal health
For the first time, the American Academy of Sleep Medicine has released official consensus recommendations for the amount of sleep needed to promote optimal health in children and teenagers to avoid the health risks of insufficient sleep.

Related Sleep Reading:

Why We Sleep: Unlocking the Power of Sleep and Dreams
by Matthew Walker PhD (Author)

Go the F**k to Sleep
by Adam Mansbach (Author), Ricardo Cort├ęs (Illustrator)

Sleep Smarter: 21 Essential Strategies to Sleep Your Way to A Better Body, Better Health, and Bigger Success
by Shawn Stevenson (Author)

Precious Little Sleep: The Complete Baby Sleep Guide for Modern Parents
by Alexis Dubief (Author)

Twelve Hours' Sleep by Twelve Weeks Old: A Step-by-Step Plan for Baby Sleep Success
by Suzy Giordano (Author), Lisa Abidin (Author)

Healthy Sleep Habits, Happy Child, 4th Edition: A Step-by-Step Program for a Good Night's Sleep
by Marc Weissbluth M.D. (Author)

The Sleep Solution: Why Your Sleep is Broken and How to Fix It
by W. Chris Winter M.D. (Author)

Sleep: The Myth of 8 Hours, the Power of Naps, and the New Plan to Recharge Your Body and Mind
by Nick Littlehales (Author)

Morning Magic: How to Sleep Better, Wake Up Productive, and Create a Marvelous Morning Routine
by Level-Up Star Publishing

Where Do Steam Trains Sleep at Night?
by Brianna Caplan Sayres (Author), Christian Slade (Illustrator)

Best Science Podcasts 2018

We have hand picked the best science podcasts for 2018. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Where Joy Hides
When we focus so much on achievement and success, it's easy to lose sight of joy. This hour, TED speakers search for joy in unexpected places, and explain why it's crucial to a fulfilling life. Speakers include inventor Simone Giertz, designer Ingrid Fetell Lee, journalist David Baron, and musician Meklit Hadero.
Now Playing: Science for the People

#500 500th Episode
This week we turn 500! To celebrate, we're taking the opportunity to go off format, talk about the journey through 500 episodes, and answer questions from our lovely listeners. Join hosts Bethany Brookshire and Rachelle Saunders as we talk through the show's history, how we've grown and changed, and what we love about the Science for the People. Here's to 500 more episodes!