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 One step closer to reality
20.04.2018 | Max-Planck-Institut für Entwicklungsbiologie

nachricht The dark side of cichlid fish: from cannibal to caregiver
20.04.2018 | Veterinärmedizinische Universität Wien

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

Im Focus: Basel researchers succeed in cultivating cartilage from stem cells

Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.

Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...

Im Focus: Like a wedge in a hinge

Researchers lay groundwork to tailor drugs for new targets in cancer therapy

In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

Magnetic nano-imaging on a table top

20.04.2018 | Physics and Astronomy

Start of work for the world's largest electric truck

20.04.2018 | Interdisciplinary Research

Atoms may hum a tune from grand cosmic symphony

20.04.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>