Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Overworked brains release adenosine to slow cells, trigger sleep, UT Southwestern researchers find

21.04.2005


Why people get drowsy and fall asleep, and how caffeine blocks that process, are the subjects of a new study by researchers at UT Southwestern Medical Center. When cells in a certain part of the brain become overworked, a compound in the brain kicks in, telling them to shut down. This causes people to become drowsy and fall asleep. Alter that natural process by adding coffee or tea, and the brain compound – called adenosine – is blocked, and people stay awake.

These findings, available online and in the April 21 issue of the journal Neuron, offer new clues regarding the function of the brain in the body’s natural sleep process, as well as potential targets for future treatments for insomnia and other sleep problems. Prolonged increased neural activity in the brain’s arousal centers triggers the release of adenosine, which in turn slows down neural activity in the arousal center areas. Because the arousal centers control activity throughout the entire brain, the process expands outward and causes neural activity to slow down everywhere in the brain.

"Insomnia and chronic sleep loss are very common problems," said Dr. Robert W. Greene, professor of psychiatry and senior author of the study. "In addition, all the major psychiatric disorders, including depression, schizophrenia and post-traumatic stress disorder have sleep disruption as a prominent symptom.



"If we can understand better some of the factors involved in what makes us normally fall asleep, we can start to understand what might be going wrong when we don’t."

Showing that increased brain cell activity triggers drowsiness also explains how caffeine works in helping people fight sleep. "We knew that coffee kept us awake," Dr. Greene said. "Now we know why: Coffee and tea are blocking the link between the prolonged neural activity of waking and increased levels of adenosine in cells, which is why they prevent us from getting drowsy."

Past studies by Dr. Greene and his colleagues have shown that adenosine may act as a "fatigue factor." When adenosine levels increase in the arousal centers -- as happens with prolonged waking -- mammals tend to fall asleep. But what hasn’t been known before is what triggers the release of adenosine to induce sleep.

"Neurons in the brain do things -- such as talk to each other, process information and coordinate body activities – which is called neural activity," said Dr. Greene, who holds the Sherry Knopf Crasilneck Distinguished Chair in Psychiatry, in Honor of Albert Knopf. "When they do this over a long period of time, more and more adenosine is released and feeds back onto the cells to quiet them down. It’s like telling them: ’You guys have worked too hard; take it easy, and refresh yourselves.’

"What we have shown in our study is that it’s this prolonged neural activity of being awake that causes adenosine levels to go up, which in turn makes a person feel drowsy. It’s the brain’s way of achieving a proper balance between the neural activity of waking and the need for sleep. If something goes wrong with this adenosine system, you may end up with insomnia."

Other UT Southwestern researchers on the study were Dr. David Chapman, a postdoctoral researcher in psychiatry, and Dr. Dario Brambilla, a former postdoctoral researcher in psychiatry, now at the University of Milan Medical School in Italy.

Donna Steph Hansard | EurekAlert!
Further information:
http://www.utsouthwestern.edu

More articles from Life Sciences:

nachricht Mutation that causes autism and intellectual disability makes brain less flexible
20.11.2018 | Institute of Science and Technology Austria

nachricht The sweet side of reproductive biology
20.11.2018 | Leibniz-Institut für Nutzierbiologie (FBN)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: UNH scientists help provide first-ever views of elusive energy explosion

Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.

Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Optical Coherence Tomography: German-Japanese Research Alliance hosted Medical Imaging Conference

19.11.2018 | Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

 
Latest News

Mutation that causes autism and intellectual disability makes brain less flexible

20.11.2018 | Life Sciences

The sweet side of reproductive biology

20.11.2018 | Life Sciences

Fading stripes in Southeast Asia: First insight into the ecology of an elusive and threatened rabbit

20.11.2018 | Ecology, The Environment and Conservation

VideoLinks
Science & Research
Overview of more VideoLinks >>>