Featured Research

from universities, journals, and other organizations

Discovery Clarifies Role Of Peptide In Biological Clock

Date:
March 18, 2005
Source:
Washington University In St. Louis
Summary:
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.

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.

Related Articles


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."


Story Source:

The above story is based on materials provided by Washington University In St. Louis. Note: Materials may be edited for content and length.


Cite This Page:

Washington University In St. Louis. "Discovery Clarifies Role Of Peptide In Biological Clock." ScienceDaily. ScienceDaily, 18 March 2005. <www.sciencedaily.com/releases/2005/03/050309150837.htm>.
Washington University In St. Louis. (2005, March 18). Discovery Clarifies Role Of Peptide In Biological Clock. ScienceDaily. Retrieved March 29, 2015 from www.sciencedaily.com/releases/2005/03/050309150837.htm
Washington University In St. Louis. "Discovery Clarifies Role Of Peptide In Biological Clock." ScienceDaily. www.sciencedaily.com/releases/2005/03/050309150837.htm (accessed March 29, 2015).

Share This


More From ScienceDaily



More Plants & Animals News

Sunday, March 29, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

New Arthropod Fossil Might Be Relative Of Spiders, Scorpions

New Arthropod Fossil Might Be Relative Of Spiders, Scorpions

Newsy (Mar. 29, 2015) A 508-million-year-old arthropod that swam in the Cambrian seas is thought to share a common ancestor with spiders and scorpions. Video provided by Newsy
Powered by NewsLook.com
Vietnam Rice Boom Piles Pressure on Farmers and the Environment

Vietnam Rice Boom Piles Pressure on Farmers and the Environment

AFP (Mar. 29, 2015) Vietnam&apos;s drive to become the world&apos;s leading rice exporter is pushing farmers in the fertile Mekong Delta to the brink, say experts, with mounting costs to the environment. Duration: 02:35 Video provided by AFP
Powered by NewsLook.com
Raw: Lioness Has Rare Five-Cub Litter

Raw: Lioness Has Rare Five-Cub Litter

AP (Mar. 27, 2015) A lioness in Pakistan has given birth to five cubs, twice the usual size of a litter. Queen gave birth to two other cubs just nine months ago. (March 27) Video provided by AP
Powered by NewsLook.com
Jockey Motion Tracking Reveals Racing Prowess

Jockey Motion Tracking Reveals Racing Prowess

Reuters - Innovations Video Online (Mar. 26, 2015) Using motion tracking technology, researchers from the Royal Veterinary College (RVC) are trying to establish an optimum horse riding style to train junior jockeys, as well as enhance safety, health and well-being of both racehorses and jockeys. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins