Mon, Mar 27, 2017 | updated 10:03 PM IST

Glial- new player in feeding behaviour

Updated: Oct 19, 2016 13:49 IST

Washington D.C. [USA], Oct. 19 (ANI): A new study has found out that brain cells called glial cells play a critical role in controlling appetite and feeding behaviour.

In a study by of mice, the MIT neuroscientists found that activating these cells stimulates overeating, and that when the cells are suppressed, appetite is also suppressed.

The findings could offer scientists a new target for developing drugs against obesity and other appetite-related disorders, the researchers said.

The study is also the latest in recent years to implicate glial cells in important brain functions. Until about 10 years ago, glial cells were believed to play more of a supporting role for neurons.

"In the last few years, abnormal glial cell activities have been strongly implicated in neurodegenerative disorders. There is more and more evidence to point to the importance of glial cells in modulating neuronal function and in mediating brain disorders," said senior author Guoping Feng.

It has long been known that the hypothalamus, an almond-sized structure located deep within the brain, controls appetite as well as energy expenditure, body temperature, and circadian rhythms including sleep cycles.

While performing studies on glial cells in other parts of the brain, researcher Naiyan Chen noticed that the hypothalamus also appeared to have a lot of glial cell activity.

"I was very curious at that point what glial cells would be doing in the hypothalamus, since glial cells have been shown in other brain areas to have an influence on regulation of neuronal function," she said.

Within the hypothalamus, scientists have identified two key groups of neurons that regulate appetite, known as AgRP neurons and POMC neurons. AgRP neurons stimulate feeding, while POMC neurons suppress appetite.

Until recently it has been difficult to study the role of glial cells in controlling appetite or any other brain function, because scientists haven't developed many techniques for silencing or stimulating these cells, as they have for neurons. Glial cells, which make up about half of the cells in the brain, have many supporting roles, including cushioning neurons and helping them form connections with one another.

In this study, the research team used a new technique developed at the University of North Carolina to study a type of glial cell known as an astrocyte. Using this strategy, researchers can engineer specific cells to produce a surface receptor that binds to a chemical compound known as CNO, a derivative of clozapine. Then, when CNO is given, it activates the glial cells.

The MIT team found that turning on astrocyte activity with just a single dose of CNO had a significant effect on feeding behavior.

"When we gave the compound that specifically activated the receptors, we saw a robust increase in feeding," Chen said. "Mice are not known to eat very much in the daytime, but when we gave drugs to these animals that express a particular receptor, they were eating a lot."

The researchers also found that in the short term (three days), the mice did not gain extra weight, even though they were eating more.

"This raises the possibility that glial cells may also be modulating neurons that control energy expenditures, to compensate for the increased food intake," Chen said. "They might have multiple neuronal partners and modulate multiple energy homeostasis functions all at the same time."

When the researchers silenced activity in the astrocytes, they found that the mice ate less than normal.

Still unknown is how the astrocytes exert their effects on neurons. Some recent studies have suggested that glial cells can secrete chemical messengers such as glutamate and ATP; if so, these "gliotransmitters" could influence neuron activity.

Another hypothesis is that instead of secreting chemicals, astrocytes exert their effects by controlling the uptake of neurotransmitters from the space surrounding neurons, thereby affecting neuron activity indirectly.

Feng now plans to develop new research tools that could help scientists learn more about astrocyte-neuron interactions and how astrocytes contribute to modulation of appetite and feeding. He also hopes to learn more about whether there are different types of astrocytes that may contribute differently to feeding behavior, especially abnormal behavior.

"We really know very little about how astrocytes contribute to the modulation of appetite, eating, and metabolism," he said. "In the future, dissecting out these functional differences will be critical for our understanding of these disorders."

The study has been published in eLife. (ANI)

Washington D.C. [USA], Mar. 26 (ANI): Attention dog lovers! With just six months of training, a German Shepherd can accurately detect breast cancer, a study finds.

Full Story >>

Washington D.C. [USA], Mar. 26 (ANI): A recent study has found that a sleepless night impairs your ability to interpret subtle expressions of happiness and sadness.

Full Story >>

Washington D.C. [USA], Mar. 26 (ANI): When it comes to new moms' workout programs, less is more and so, according to a Kansas State University researcher, new moms may need a bit more flexibility and support to ease back into exercise after giving birth.

Full Story >>

New approach to diagnosing mental disorders

Updated: Mar 26, 2017 10:48 IST

Washington D.C. [USA], Mar. 26 (ANI): A consortium of psychiatrists and psychologists has proposed a new approach to diagnosing mental disorders.

Full Story >>

Washington D.C. [USA], Mar. 26 (ANI): Boosting natural brain opioids may be a better way to treat anxiety, according to a recent study.

Full Story >>

Fecal transplant offers hope for autistic kids

Updated: Mar 26, 2017 09:37 IST

Washington D.C. [USA], Mar. 26 (ANI): In this new era of medical therapy dawning, fecal transplants are poised to help fight a range of conditions, from deadly superbugs to obesity and now, autism is in the firing line.

Full Story >>

Thiruvallur (Chennai) [India], Mar. 25 (ANI): A highly contagious viral disease of cattle and swine, Foot-and-Mouth Disease (FMD) has affected Karani village on the outskirts of Tamil Nadu's Tiruvallur district.

Full Story >>

New Delhi [India], Mar. 25 (ANI): The findings of the National Family Health Survey 2015-16 confirm what we all knew from clinical evidence - that hypertension has become a major health concern among the Indian population, with as many as 22% Indians hypertensive.

Full Story >>

Washington D.C. [USA], Mar. 25 (ANI): A prescription weight-loss medication can decrease the urge to use opiates such as oxycodone, according to a recent study.

Full Story >>

Washington D.C. [USA], Mar. 25 (ANI): A team of researchers has discovered a new gene that is associated with Tau accumulation, which is one of the defining features of Alzheimer disease (AD).

Full Story >>

Washington D.C. [USA], Mar. 25 (ANI): All it takes is the flip of a protein "switch" within the tiny wire-like capillaries of the brain to increase the blood flow that ensures optimal brain function.

Full Story >>

Washington D.C. [USA], Mar. 25 (ANI): Scientists have found that stem cell therapy repairs damaged lungs - raising hopes of a cure for the crippling chronic obstructive pulmonary disease (COPD) and cystic fibrosis.

Full Story >>

New method can cut dental implant failure

Updated: Mar 25, 2017 09:34 IST

Washington D.C. [USA], Mar. 25 (ANI): A team of researchers has come up with a new method to reduce dental implant failure.

Full Story >>

Washington D.C. [USA], Mar. 25 (ANI): A team of researchers has come up with a fluorogenic probe that can detect the activity of multidrug-resistant pathogens in an assay system.

Full Story >>

Virus hydrophobicity can help purify vaccines

Updated: Mar 25, 2017 07:46 IST

Washington D.C. [USA], Mar. 25 (ANI): A team of researchers has found that hydrophobic proteins on virus surfaces can help purify vaccines.

Full Story >>

Washington D.C. [USA], Mar. 25 (ANI): A team of researchers has shed light on why survivors of childhood brain tumours may be prone to heart disease, stroke, type 2 diabetes and early death.

Full Story >>

New Delhi [India], Mar. 24 (ANI): Continuing its efforts to raise awareness on tuberculosis and its diagnosis, Division of Clinical Microbiology & Molecular Medicine Department of Laboratory Medicine, AIIMS, and BD (Becton Dickinson India) for the third consecutive year organized a symposium today on "challenges in diagnosis and eradication of tuberculosis".

Full Story >>

New Delhi [India], Mar. 24 (ANI): On the solemn occasion of World Tuberculosis (TB) Day, Members of Parliament, policymakers, TB patients, survivors, and citizens of the civil society gathered at India Gate on Thursday, March 23 to pay tribute to the nearly five lakh lives lost due to this disease last year.

Full Story >>

New Delhi [India], Mar. 24 (ANI): Emergence of multi drug resistant TB and complications aggravated by high rates of co-infection with HIV-AIDS has renewed the threat of TB epidemic in India. With widespread prevalence of the infection, children experience a serious risk of contracting Tuberculosis, especially if they are under-nourished.

Full Story >>

New Delhi [India], Mar. 24 (ANI): Tuberculosis can affect any age, caste or class and it is one of the top 10 causes of death across the globe, ranking above HIV and malaria.

Full Story >>