Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Discovery clarifies role of peptide in biological clock

07.03.2005


Uncoupling the clock

A biologist at Washington University in St. Louis is giving the VIP treatment to laboratory mice in hopes of unraveling more clues about our biological clock. VIP is not "very important person," but vasoactive intestinal polypeptide (VIP), a neuropeptide originally found in the gut, that is also made by a specialized group of neurons in the brain.

Erik Herzog, Ph.D., Washington University assistant professor of Biology in Arts & Sciences, has discovered that VIP is needed by the brain’s biological clock to coordinate daily rhythms in behavior and physiology. Neurons in the biological clock, an area called the suprachiasmatic nucleus (SCN), keep 24-hour time and are normally synchronized as a well-oiled marching band coming onto the field at half time. Herzog and graduate student, Sara Aton, found that mice lacking the gene that makes VIP or lacking the receptor molecule for VIP suffer from internal de-synchrony. When they recorded the electrical activity of SCN neurons from these mice, they found that many had lost their beat while others were cycling but unable to synch to each other.



But when Herzog and Aton added VIP to the mice cells, the synchronicity was restored, showing that VIP couples pacemaker cells and drives rhythms in slave cells.

"VIP between SCN neurons is like a rubber band between the pendulums of two grandfather clocks, helping to synchronize their timing. Some researchers had proposed that knocking out VIP or the receptor for it stopped the clock," Herzog said. "We’ve found that the biological clock is still running, but its internal synchrony is uncoordinated. This causes irregular patterns of sleep and wake, for example."

The study was published on-line in Nature Neuroscience on March 6, 2005. Herzog’s work is funded by the National Institutes of Health.

"In a light-dark schedule, these mice looked normal, but as soon as you leave off the lights, they reveal their internal de-synchrony," he said. "The mice showed multiple rhythms, getting up both earlier and earlier and later and later on subsequent days so that their daily activity patterns were splitting apart."

Herzog and Aton recorded neuron activity from the SCN using a multielectrode array with 60 electrodes upon which they place SCN cells, a "clock in a dish." This enabled them to record data from many cells for many days.

"We found that the VIP mutants, indeed, can generate circadian rhythms, but the neurons can’t synchronize to each other," Herzog said. "We showed that we could restore rhythms to the arrhythmic neurons and synchrony to the SCN by providing VIP once a day."

The SCN is a part of the hypothalamus that can be found on the bottom of the brain just above the roof of your mouth where your optic nerves cross. There are roughly 10,000 neurons in this nucleus on either side of your brain. The timekeeping mechanism in these cells depends on daily cycles in gene activity.

Herzog found in his latest study that the percentage of rhythmic cells in the mutant SCN was very low, and he believes these rhythmic neurons are specialized circadian pacemakers.

"We suspect that at least some of the pace making cells in the SCN are VIP cells, and one of the things we’ll try to do next is confirm this. We will also try to understand better how VIP synchronizes pacemakers," he said.

It is surprising that the process is regulated by a peptide, usually a slow signaling agent, rather than a neurotransmitter, associated with fast events, Herzog said.

"We’re trying to understand the mechanics of how the system synchronizes and the secondary messenger systems as well," Herzog said. "We’re getting closer to the heart and soul of circadian rhythmicity by uncoupling the (biological) clock."

Tony Fitzpatrick | EurekAlert!
Further information:
http://www.wustl.edu

More articles from Life Sciences:

nachricht Münster University researchers develop new synthesis method for producing fluorinated piperidines
22.01.2019 | Westfälische Wilhelms-Universität Münster

nachricht New blood vessel system discovered in bones
22.01.2019 | Universität Duisburg-Essen

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Energizing the immune system to eat cancer

Abramson Cancer Center study identifies method of priming macrophages to boost anti-tumor response

Immune cells called macrophages are supposed to serve and protect, but cancer has found ways to put them to sleep. Now researchers at the Abramson Cancer...

Im Focus: Ten-year anniversary of the Neumayer Station III

The scientific and political community alike stress the importance of German Antarctic research

Joint Press Release from the BMBF and AWI

The Antarctic is a frigid continent south of the Antarctic Circle, where researchers are the only inhabitants. Despite the hostile conditions, here the Alfred...

Im Focus: Ultra ultrasound to transform new tech

World first experiments on sensor that may revolutionise everything from medical devices to unmanned vehicles

The new sensor - capable of detecting vibrations of living cells - may revolutionise everything from medical devices to unmanned vehicles.

Im Focus: Flying Optical Cats for Quantum Communication

Dead and alive at the same time? Researchers at the Max Planck Institute of Quantum Optics have implemented Erwin Schrödinger’s paradoxical gedanken experiment employing an entangled atom-light state.

In 1935 Erwin Schrödinger formulated a thought experiment designed to capture the paradoxical nature of quantum physics. The crucial element of this gedanken...

Im Focus: Nanocellulose for novel implants: Ears from the 3D-printer

Cellulose obtained from wood has amazing material properties. Empa researchers are now equipping the biodegradable material with additional functionalities to produce implants for cartilage diseases using 3D printing.

It all starts with an ear. Empa researcher Michael Hausmann removes the object shaped like a human ear from the 3D printer and explains:

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Our digital society in 2040

16.01.2019 | Event News

11th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Aachen, 3-4 April 2019

14.01.2019 | Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

 
Latest News

Mechanical engineers develop process to 3D print piezoelectric materials

22.01.2019 | Materials Sciences

Energizing the immune system to eat cancer

22.01.2019 | Health and Medicine

Early Prediction of Alzheimer’s Progression in Blood

22.01.2019 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>