Navigation Links
Sleep chemical central to effectiveness of deep brain stimulation
Date:12/23/2007

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 Parkinsons 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 Parkinsons disease and who have severe tremor, and its 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 patients 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 its the brains way of telling us that its been a long day, weve expended a lot of energy, and its 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 DBSs 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. Weve all been focused on what is happening to the nerve cells in the brain, but it may be that weve been looking at the wrong cell type.

Nedergaards 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 brains 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, its 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 Nedergaards 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 Alzheimers 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.


'/>"/>

Contact: Tom Rickey
tom_rickey@urmc.rochester.edu
585-275-7954
University of Rochester Medical Center
Source:Eurekalert

Related medicine news :

1. Time to Set Kids Back-to-School Sleep Clocks
2. AASM encourages those student-athletes at risk for developing osa to visit a sleep clinic
3. Sleepless Kids Are Troubled Kids
4. Jefferson specialists studying innovative surgery for effectively treating sleep apnea
5. Work time is the largest influence to the duration of a persons sleep
6. Passive smoking increases sleep disturbance among pregnant women
7. Minorities more likely to have sleep durations associated with increased mortality
8. Lack of sleep among new school-goers leads to behavioral, cognitive problems
9. Work Time Predicts Sleep Time
10. Nicotine in breast milk disrupts infants sleep patterns
11. Pain patients at risk for sleep apnea
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/26/2016)... ... 26, 2016 , ... Pixel Film Studios Released ProSlice Levels, a Media Slicing ... their videos a whole new perspective by using the title layers in ProSlice ... , ProSlice Levels contains over 30 Different presets to choose from. FCPX ...
(Date:6/26/2016)... (PRWEB) , ... June 26, 2016 , ... ... fertility once they have been diagnosed with endometriosis. These women need a treatment ... also require a comprehensive approach that can help for preservation of fertility and ...
(Date:6/25/2016)... , ... June 25, 2016 , ... The temporary closing of Bruton Memorial Library on ... Observer , brings up a new, often overlooked aspect of head lice: the parasite’s ability ... fumigation is not a common occurrence, but a necessary one in the event that lice ...
(Date:6/25/2016)... , ... June 25, 2016 , ... As a lifelong ... Cum Laude and his M.D from the David Geffen School of Medicine at UCLA. ... to Los Angeles to complete his fellowship in hematology/oncology at the UCLA-Olive View-Cedars Sinai ...
(Date:6/25/2016)... ... June 25, 2016 , ... Conventional wisdom preaches the benefits of ... of the latter, setting the bar too high can result in disappointment, perhaps even ... progress toward their goal. , Research from PsychTests.com reveals that behind ...
Breaking Medicine News(10 mins):
(Date:6/23/2016)... Capricor Therapeutics, Inc. ... company focused on the discovery, development and commercialization ... in its ongoing randomized HOPE-Duchenne clinical trial (Halt ... its 24-patient target. Capricor expects the trial to ... 2016, and to report top line data from ...
(Date:6/23/2016)...  Astellas today announced the establishment of Astellas Farma Colombia (AFC), a new affiliate with operations headquartered in ... . ... ... ... Astellas ...
(Date:6/23/2016)... June 23, 2016  Experian Health, the ... transforming the patient payment and care experience, ... new products and services that will enhance ... cycle offerings. These award-winning solutions will enable ... remain compliant in an ever-changing environment and ...
Breaking Medicine Technology: