Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Unconventional brain circuits offer clues to insomnia-obesity connection

13.04.2005


NationaUnconventional wiring of the brain circuits that govern sleep and waking might explain the prevalence of insomnia and the condition’s association with obesity, according to new work published in the April issue of Cell Metabolism. Characterized by a chronic inability to fall asleep or remain sleeping, insomnia is estimated to affect one in every eight Americans.



By finding ways to interfere with that unconventional wiring, scientists may advance on new treatments for insomnia, the researchers said. Natural variation in this brain system might also explain differences among people in their susceptibility to sleep disturbances.

The researchers found that so-called hypocretin neurons--having important roles in both arousal and appetite--lack the ability of most neurons to filter "noise" from signal, reported Tamas Horvath and Xiao-Bing Gao of Yale University School of Medicine. The neurons also rapidly reorganize themselves, becoming even more excitable, in response to stresses such as food deprivation, they found.


"The cell bodies of most neurons act as a filter," sorting through a multitude of signals to eliminate noise and generate an appropriate response, Horvath said. "In contrast, it appears that the basic wiring of hypocretin neurons allows noise to become the major signal."

As obesity has reached epidemic proportions, the incidence of insomnia and sleep deprivation has also risen. Studies of this apparent insomnia-obesity association have suggested a causal link between the two, but the underlying mechanism has remained unclear. The new findings of hypocretin neurons offer some possible clues, Horvath said.

Scientists discovered hypocretin neurons while studying narcolepsy, a condition marked by sudden bouts of deep sleep. Narcolepsy generally stems from a shortage or malfunction of hypocretin neurons. The neurons also induce appetite, an important activity for the control of food intake. Yet the integration of the brain cells’ roles in arousal and appetite remains largely unexplored, Horvath said.

In a series of experiments in brain slices and in mice, the researchers examined the organization and stability of inputs to hypocretin cell bodies, which act as filters in other brain cells. They found that hypocretin neurons have an "unorthodox" organization in which excitatory currents exert control on nerve cell bodies with minimal inhibitory inputs to filter them.

Overnight food deprivation promoted the formation of more excitatory inputs. Those new inputs were reversed upon refeeding, they reported, an indication of the extreme plasticity of the hypocretin system to prevailing conditions.

That sensitivity and adaptability makes sense, given the neurons’ role as the body’s natural alarm, rousing one from slumber in response to external cues, Horvath said. However, the structure of the system might also explain the prevalence of sleep disorders and, perhaps, the associated rise in obesity.

"In an evolutionary sense, the response of the hypocretin system to small stimuli would have been necessary for survival," he said. "But in today’s chronically stressful environment, the circuitry may also be an underlying cause of insomnia and associated metabolic disturbances, including obesity."

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

More articles from Life Sciences:

nachricht More genes are active in high-performance maize
19.01.2018 | Rheinische Friedrich-Wilhelms-Universität Bonn

nachricht How plants see light
19.01.2018 | Albert-Ludwigs-Universität Freiburg im Breisgau

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

More genes are active in high-performance maize

19.01.2018 | Life Sciences

How plants see light

19.01.2018 | Life Sciences

Artificial agent designs quantum experiments

19.01.2018 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>