Navigation Links
Scientists identify another piece of the weight-control puzzle
Date:8/10/2008

BOSTON Controlling body weight is a complicated process, as any frustrated dieter might attest. But as scientists continue to investigate the brain's intricate neurocircuitry and its role in maintaining energy balance, they are forming a clearer picture of the myriad events that lead to weight gain and weight loss.

In the August 10 on-line issue of Nature Neuroscience, a study led by scientists at Beth Israel Deaconess Medical Center (BIDMC) identifies another piece of this complex puzzle, demonstrating that the neurotransmitter GABA --one of the master communicators among neurons plays a role in controlling energy balance.

"Body weight maintenance is made up of three basic stages," explains the paper's senior author Bradford Lowell, MD, PhD, an investigator in the Division of Endocrinology, Diabetes and Metabolism at BIDMC whose laboratory is working to identify the specific neurocircuits responsible for controlling food intake and/or energy through functional neuroanatomical mapping studies.

"In the first stage, the brain receives sensory input from the body [including information provided by circulating hormones such as leptin and ghrelin and from fuels such as glucose and fatty acids]," says Lowell, who is also a Professor of Medicine at Harvard Medical School.

In the second stage, he adds, the brain integrates this sensory information with cues it has received from the environment (such as aromas and other enticements) along with information gathered from the organism's emotional state. Then, in the final stage, the brain's neurocircuitry takes over, enabling the brain to make appropriate alterations in food intake and energy expenditure in order to maintain energy balance and prevent weight gain and obesity.

Previous work had primarily focused on identifying the neuropeptides involved in this process. And indeed, this group of neurotransmitters often proves essential to maintaining energy balance but not always.

"It is well known that AgRP [Agouti-related protein] neurons play a critical role in feeding and energy balance regulation," explains Qingchun Tong, PhD, a postdoctoral fellow in the Lowell laboratory and the study's first author. "However, the deletion of AgRP and NPY [two neuropeptides released from the AgRP neurons] produces little metabolic effect."

An alternate theory proposed that release of the GABA neurotransmitter was mediating the function of AgRP neurons, an idea that had long been postulated but never examined.

To test this hypothesis, Tong and his colleagues generated a group of mice with disrupted release of GABA specifically from the AgRP neurons. As predicted, the genetically altered mice exhibited profound metabolic changes.

"The mice with AgRP neuron-specific disruption of GABA release were lean, had higher energy expenditure and showed resistance to diet-induced obesity," says Tong. "We also found that these animals showed reduced food intake response to the hormone ghrelin. This suggests to us that the neurocircuit engaging GABA release from the AgRP neurons mediates at least part of ghrelin's appetite-stimulating action."

A series of studies to examine the function of glutamate and GABA release from other groups of neurons are currently underway as investigators continue to dissect the brain's neurocircuitry.

"As these new findings demonstrate, GABA release is an important component that mediates the function of AgRP neurons," says Tong. "Discoveries such as this will ultimately help us to design an efficient strategy to tackle the current epidemic of obesity and metabolic disease."


'/>"/>

Contact: Bonnie Prescott
bprescot@bidmc.harvard.edu
617-667-7306
Beth Israel Deaconess Medical Center
Source:Eurekalert

Related medicine news :

1. New prion protein discovered by Canadian scientists may offer insight into mad cow disease
2. Scientists Probe Sepsis Deadly Secrets
3. Scientists puzzled by severe allergic reaction to cancer drug in the middle Southern US
4. Scientists Develop Natural Protection for Stored Foods
5. Scientists detect presence of marburg virus in african fruit bats
6. Scientists Spot Brains Free Will Center
7. Scientists ID Likely Culprit in Popcorn Lung
8. Scientists explain how insulin secreting cells maintain their glucose sensitivity
9. Scripps Research scientists shed new light on how antibodies fight HIV
10. Scientists, physicians present latest findings in personalized cancer treatment and prevention
11. Scientists demonstate link between genetic variant and effectiveness of smoking cessation meds
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:2/5/2016)... York, New York (PRWEB) , ... February 05, 2016 , ... ... life? The answer may be at the tips of your toes. Foot massage, whether ... as well as pure comfort and relaxation. The American Board of Multiple Specialties ...
(Date:2/5/2016)... ... February 05, 2016 , ... ... franchises from across the country gathered at the La Valencia Hotel in San ... PROSHRED Chicago was named the year’s most outstanding franchise, walking away with ...
(Date:2/5/2016)... ... 05, 2016 , ... Pivot Point Consulting, a leading national ... & Services for HIT Implementation Support & Staffing report with an outstanding score ... by healthcare executives, managers and clinicians representing over 4,500 hospitals and 2,500 clinics. ...
(Date:2/5/2016)... (PRWEB) , ... February 05, 2016 , ... Colorize ... from on one drop zone to the next using Colorize's dynamic moving camera. Colorize ... project. This package includes a 3D slideshow environment with 1 to 5 focus points ...
(Date:2/5/2016)... ... 05, 2016 , ... Calls Blacklist has just been updated by mobile app ... the developer has fixed known bugs within the app. Calls Blacklist allows its users ... not consuming any of their device’s battery power or memory. It provides a powerful ...
Breaking Medicine News(10 mins):
(Date:2/4/2016)... Feb. 4, 2016  SciClone Pharmaceuticals, Inc. (NASDAQ: ... has entered into a settlement agreement with the ... resolving the SEC,s investigation into possible violations of ... terms of the settlement agreement, SciClone has agreed ... disgorgement, pre-judgment interest and a penalty.  This payment ...
(Date:2/4/2016)... -- Global Immunology Market to 2022 - Large ... growth Summary Immune-mediated inflammatory diseases are ... affect 5–7% of western populations. Although they are ... key patient demographics, they are pathophysiologically linked, being ... inappropriate immune response. Generally, disease-modifying anti-rheumatic drugs, a ...
(Date:2/4/2016)...  Aethlon Medical, Inc. (Nasdaq: AEMD ), ... treat life-threatening diseases, today announced results for the ... 2015. --> --> ... our last quarterly call, we strategically advanced pre-clinical ... to establish the Aethlon Hemopurifier® as a leading ...
Breaking Medicine Technology: