Science Current Events | Science News | Brightsurf.com
 
Email a Friend Send to a friend
Printer Friendly Print Sleep chemical central to effectiveness of deep brain stimulation

Sleep chemical central to effectiveness of deep brain stimulation

December 26, 2007

A brain chemical that makes us sleepy also appears to play a central role in the success of deep brain stimulation to ease symptoms in patients with Parkinson's disease and other brain disorders. The surprising finding is outlined in a paper published online Dec. 23 in Nature Medicine.

The work shows that adenosine, a brain chemical most widely known as the cause of drowsiness, is central to the effect of deep brain stimulation, or DBS. The technique is used to treat people affected by Parkinson's disease and who have severe tremor, and it's also being tested in people who have severe depression or obsessive-compulsive disorder.




Patients typically are equipped with a "brain pacemaker," a small implanted device that delivers carefully choreographed electrical signals to a very precise point in the patient's brain. The procedure disrupts abnormal nerve signals and alleviates symptoms, but doctors have long debated exactly how the procedure works.

The new research, by a team of neuroscientists and neurosurgeons at the University of Rochester Medical Center, gives an unexpected nod to a role for adenosine and to cells called astrocytes that were long overlooked by neuroscientists.

"Certainly the electrical effect of the stimulation on neurons is central to the effect of deep brain stimulation," said Maiken Nedergaard, M.D., Ph.D., the neuroscientist and professor in the Department of Neurosurgery who led the research team. "But we also found a very important role for adenosine, which is surprising."

Adenosine in the brain is largely a byproduct of the chemical ATP, the source of energy for all our cells. Adenosine levels in the brain normally build as the day wears on, and ultimately it plays a huge role in making us sleepy - it's the brain's way of telling us that it's been a long day, we've expended a lot of energy, and it's time to go to bed.

The scientists say the role of adenosine in deep brain stimulation has not been realized before. Even though scientists have recognized its ability to inhibit brain cell signaling, they did not suspect any role as part of DBS's effect of squelching abnormal brain signaling.

"There are at least a dozen theories of what is happening in the brain when deep brain stimulation is applied, but the fact is that no one has really understood the process completely," said Robert Bakos, M.D., a neurosurgeon at the University of Rochester and a co-author of the paper, who has performed more than 100 DBS surgeries in the last decade. "We've all been focused on what is happening to the nerve cells in the brain, but it may be that we've been looking at the wrong cell type."

Nedergaard's team showed that the electrical pulses that are at the heart of DBS evoke those other cells - astrocytes - in the area immediately around the surgery to release ATP, which is then broken into adenosine. The extra adenosine reduces abnormal signaling among the brain's neurons.

The team also showed that in mice, an infusion of adenosine itself, without any deep brain stimulation, reduced abnormal brain signaling. They also demonstrated that in mice whose adenosine receptors had been blocked, DBS did not work; and they showed that a drug like caffeine that blocks adenosine receptors (the reason why caffeine helps keep us awake) also diminishes the effectiveness of DBS.

"It may be possible to enhance the effectiveness of deep brain stimulation by taking advantage of the role of agents that modulate the pathways initiated by adenosine," said Nedergaard. "Or, it's possible that one could develop another type of procedure, perhaps using local targeting of adenosine pathways in a way that does not involve a surgical procedure."

The latest work continues Nedergaard's line of research showing that brain cells other than neurons play a role in a host of human diseases. ATP in the brain is produced mainly by astrocytes, which are much more plentiful in the brain than neurons. Astrocytes were long thought of as simple support cells, but in recent years, Nedergaard and colleagues have shown that they play an important role in a host of diseases, including epilepsy, spinal cord disease, migraine headaches, and Alzheimer's disease.

The research on DBS came about as a result of a presentation Nedergaard made to colleagues about her research on astrocytes. Bakos linked her detailed description of astrocyte activity to what he sees happening in the brain when deep brain stimulation is applied. Based on Bakos' experience in the operating room and with funding from the National Institute of Neurological Disorders and Stroke, Nedergaard went back to the laboratory and analyzed the effects of deep brain stimulation in a way that no one had ever before considered.

"The correlation between what we see in the clinic and Dr. Nedergaard has found in the laboratory is really quite startling," said Bakos. "All the credit goes to her and her team. This has been a nice interchange of information between the clinic and the laboratory, to speed a discovery that really could have an impact on patients."

University of Rochester Medical Center



Related Adenosine Current Events and Adenosine News Articles Adenosine Current Events and Adenosine News RSS Adenosine Current Events and Adenosine News RSS
Drug shows promise in treating dangerous complication of erectile disorder
Thousands of men are afflicted with an embarrassing and painful condition that triggers spontaneous, long-lasting erections. There are limited treatment options, but a solution could be on the way thanks to new research at The University of Texas Health Science Center at Houston.

That '4 hour erection': new discovery may help prevent a complication of priapism
For men coping with painful erections lasting for long periods of time, or priapism, new research published online in The FASEB Journal (http://www.fasebj.org) offers hope.

Breast milk should be drunk at the same time of day that it is expressed
The levels of the components in breast milk change every 24 hours in response to the needs of the baby. A new study published in the journal Nutritional Neuroscience shows, for example, how this milk could help newborn babies to sleep.

Comprehensive cardiac CT scan may give clearer picture of significant heart disease
A team of researchers led by Massachusetts General Hospital (MGH) radiologists has developed a computed-tomography-based protocol that identifies both narrowing of coronary arteries and areas of myocardial ischemia - restricted blood flow to heart muscle tissue - giving a better indication of clinically significant coronary artery disease.

UT scientists discover link between protein and lung disease
In a development that could lead to a novel approach to the treatment of a devastating lung disease, biochemists at The University of Texas Health Science Center at Houston report they are the first to link the osteopontin (OPN) protein to chronic obstructive pulmonary disease (COPD).

Second-hand smoking results in liver disease, study finds
A team of scientists at the University of California, Riverside has found that even second-hand tobacco smoke exposure can result in nonalcoholic fatty liver disease (NAFLD), a common disease and rising cause of chronic liver injury in which fat accumulates in the liver of people who drink little or no alcohol.

Genetic variation associated with poorer response, cardiovascular outcomes with use of clopidogrel
Patients with a certain genetic variation who received the antiplatelet drug clopidogrel had a decreased platelet response to treatment and among those who had percutaneous coronary intervention (procedures such as balloon angioplasty or stent placement used to open narrowed coronary arteries) had an increased risk of having a cardiovascular event in the following year than patients who did not have this variant, according to a study in the August 26 issue of JAMA.

Building memories with actin
Memories aren't made of actin filaments. But their assembly is crucial for long-term potentiation (LTP), an increase in synapse sensitivity that researchers think helps to lay down memories.

Is 31P MRS a useful tool for evaluating early acute hepatic radiation injury?
Acute hepatic radiation injury could lead to necrosis of hepatocytes, fatty degeneration and hepatic fibrosis. At the present, the gold standard test is liver biopsy.

Protein regulates movement of mitochondria in brain cells
Scientists have identified a protein in the brain that plays a key role in the function of mitochondria - the part of the cell that supplies energy, supports cellular activity, and potentially wards off threats from disease.
More Adenosine Current Events and Adenosine News Articles
Adenosine Receptors and Parkinson's Disease (Pure and Applied Mathematics  (Academic Press), 60.)

Adenosine Receptors and Parkinson's Disease (Pure and Applied Mathematics (Academic Press), 60.)
by Hiroshi Kase (Editor), Peter J. Richardson (Editor), Peter Jenner (Editor)

This book is the first definitive overview on adenosine receptor antagonists and their application to the treatment of Parkinson's Disease. The effect of these novel non-dopamine drugs on vitro and in vivo systems clearly shows their potential for the treatment of this debilitating disease. This book covers how the Parkinson's disease antagonist drug, A2A, has been researched, developed, and tested. It is an essential book for researchers interested in the basal ganglia, purine biology, and Parkinson's Disease.

Key Features
* Discusses the discovery and development of a novel non-dopaminomimetic agent for Parkinson's disease
* Provides the first definitive overview of adenosine antagonists and their role in the treatment of Parkinson's...

Planetary Herbals Full Spectrum Cordyceps 450, 450 mg, Tablets , 120 tablets (Pack of 2)

Planetary Herbals Full Spectrum Cordyceps 450, 450 mg, Tablets , 120 tablets (Pack of 2)
by Planetary Formulas

Herbal Supplement. Chinese tonic for endurance. 0.1% Adenosine. In China, Cordyceps Sinensis is recognized as a premiere tonifier for athletes and anyone waiting to support energy and endurance. Planetary Herbs Full Spectrum Cordyceps 450 provides the sam

  Fire Away
by Adenosine



Itsuka Kit

Itsuka Kit
Adenosine Tri-Phosphate (Primary Contributor)



Adenosine Triphosphate Framed Art Poster Print by David M. Dennis, 22x18

Adenosine Triphosphate Framed Art Poster Print by David M. Dennis, 22x18
by Art.com

Art.com is the world's largest retailer of art prints, posters, photographs, and framed artwork. With our huge selection of over 400,000 prints, you'll easily find the perfect piece for your home, office, or classroom. Our art is printed on quality paper. When you order framed artwork, the piece is built by our team of in-house professionals. Visit our Amazon store today at www.amazon.com/artdotcom to find Special Offers and search for products based on 'Artist Name' and 'Subject Categories' such as Movie, Music, Vintage, TV, Children, Travel, Kitchen, Museum Art, Animals, Floral, Motivational, and Sports. Art.com is dedicated to providing you with high quality products and service by offering you 100% satisfaction guaranteed. We ship internationally to over 80 countries. Decorate your...

A3 Adenosine Receptors from Cell Biology to Pharmacology and Therapeutics

A3 Adenosine Receptors from Cell Biology to Pharmacology and Therapeutics
by Pier Andrea Borea (Editor)

This book, "A3 Adenosine Receptors from Cell Biology to Pharmacology and Therapeutics", documents the present state of knowledge of the adenosine A3 receptor. Adenosine A3 receptors are G protein-linked receptors that function in physiology and intracellular signaling and are involved in inflammatory responses and mediating cell proliferation and cell death.

The A3 receptor is increasingly being recognized for its biological roles throughout the body, and many A3 receptor ligands have proven useful in elucidating peripheral and central pathologies. This book covers a wide range of information including data from studies of theoretical, molecular and cellular pharmacology, signal transduction, integrative physiology, new drug discoveries and clinical applications. The book...

OptiATP - Creatine Nitric Oxide Power Matrix, Fruit Punch, 660 gram bottle

OptiATP - Creatine Nitric Oxide Power Matrix, Fruit Punch, 660 gram bottle
by PhytoCeutical Formulations

Welcome to OptiATP®... the most advanced, synergistic creatine product ever developed. OptiATP® is the next generation in performance creatine and has been specifically designed to support all aspects of muscular energy production for greater power, performance, and recovery. The Creatine Nitric Oxide Power Matrix in OptiATP® provides the most cutting edge and scientifically supported complex to support maximum Creatine production and greater ATP synthesis, while enhancing effectiveness by buffering lactic acid and helping to speed recovery. OptiATP® also overcomes the dehydration issue of creatine use by infusing the muscle with hydrating glycerol, as well as amino acids and electrolytes to ensure proper hydration for optimum performance, increased pump, protein synthesis and fat...

ENERGY by NOW Foods - Weight Management (90 Capsules)

ENERGY by NOW Foods - Weight Management (90 Capsules)
by NOW Foods - Weight Management

ENERGY Energy by NOW is a completely safe, comprehensive blend of nutrients and dietary ingredients that has been used with widespread success to optimize the bodys energy reserves. This intense blend of nutrients and dietary aids, including Guarana, Green Tea and Bitter Orange, provides a natural source of caffeine while supporting the bodys natural thermogenic processes simultaneously. Light-years beyond harsh Chinese herbs, this 100% natural formula is a safe and effective way to increase energy an essential requisite in weight loss and fat burning. *

Adenosine: Webster's Timeline History, 2005 - 2007

Adenosine: Webster's Timeline History, 2005 - 2007
by Icon Group International (Author)

Webster's bibliographic and event-based timelines are comprehensive in scope, covering virtually all topics, geographic locations and people. They do so from a linguistic point of view, and in the case of this book, the focus is on "Adenosine," including when used in literature (e.g. all authors that might have Adenosine in their name). As such, this book represents the largest compilation of timeline events associated with Adenosine when it is used in proper noun form. Webster's timelines cover bibliographic citations, patented inventions, as well as non-conventional and alternative meanings which capture ambiguities in usage. These furthermore cover all parts of speech (possessive, institutional usage, geographic usage) and contexts, including pop culture, the arts, social sciences...

Wish Away

Wish Away
Atp (Adenosine Tri-Phosphate) (Performer)



© 2009 BrightSurf.com