Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Food or its expectation sparks brain's hunger centers

05.10.2006
The concept of whetting the appetite by serving hors d'oeuvres before a meal may have a solid scientific basis, according to a new report in the October issue of the journal Cell Metabolism, published by Cell Press. In a study of rats trained to a strict feeding regime, researchers found that brain activity in important hunger centers spiked with the first bites of food.

"The drive to eat is massively stimulated by the start of eating," said Gareth Leng of the University of Edinburgh, who co-led the new study with Louise Johnstone. "This shows the appetizing effect of food itself as hunger circuits are acutely switched on."

The imminent expectation of food also activated certain brain cells involved in stimulating hunger in the animals, they found. The rats' optimal window for consumption was brief, however, as brain centers responsible for registering satiety--the feeling of being full or satisfied--switched on almost as soon as food hit their stomachs, Leng said.

The new study is the first to chart the sequence of changes in brain activity over the course of a meal, according to the researchers.

The researchers provided rats with food for just 2 hours per day. After 10 days on the strict regimen, food intake and body weight stabilized, the researchers reported. Rats began eating simultaneously and voraciously as soon as food was presented and stopped eating about 90 minutes later despite the continued availability of food, an indication that the animals were full.

The rats were euthanized at defined times relative to the feeding schedule and their brains analyzed. The scientists measured acute shifts in brain activity by quantifying the level of "Fos," a protein product of the "immediate early" gene c-fos. Many neurons express c-fos when activated, Leng explained, with the Fos protein, it encodes rising within an hour of c-fos expression.

Before feeding, the animals' brains exhibited little Fos in most areas examined, they found. In important hunger-moderating brain regions, cells that contain appetite-stimulating factors known as orexigenic peptides showed increased Fos at the scheduled meal time whether food was presented or not, the researchers reported.

Surprisingly, brain cells that contain "anorexigenic peptides" responsible for a loss of appetite also contained Fos at meal time, though only in the presence of food. The researchers said the finding is an indication that "satiety" circuits activate coincidentally with food intake, rather than after a threshold intake is exceeded.

"We had expected there to be a clear temporal dissociation between brain regions activated by hunger, which would peak at the scheduled time of food presentation, and regions activated when the rats stopped eating," the researchers wrote.

"Instead, neurons that release orexigenic peptides appear to be activated by the imminent expectation of food, and neurons implicated in satiety are activated as soon as any food is eaten."

Further study is required to understand how these acute shifts in brain activity are influenced by hormones, such as the fat-generated hormone leptin, that signal the body's longer-term energy status, Leng said.

Heidi Hardman | EurekAlert!
Further information:
http://www.cellmetabolism.org

More articles from Health and Medicine:

nachricht Organ-on-a-chip mimics heart's biomechanical properties
23.02.2017 | Vanderbilt University

nachricht Researchers identify cause of hereditary skeletal muscle disorder
22.02.2017 | Klinikum der Universität München

All articles from Health and Medicine >>>

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 >>>