Re: Sleep Chemical Central To Effectiveness Of Deep Brain Stimulation

[Les Combs <lescombs@xxxxxxxxxxxxx>]

I have trouble getting more than 5 to6 hours of sleep at night.  Wake up
feeling anxisious.  Sometimes I take a xanax at about 4:30 am to 5:30 am and
sleep another 3 hours or so.  I invariably have reduced symptoms during the
day when I do this.  Could the "sleep chemical" mentioned in the study hae
anything to do with this?  Anyon else out there have similar experiences?

Les


----- Original Message -----
From: "M.Schild" <mmoo@xxxxxxxxxxxxxxxx>
To: <PARKINSN@xxxxxxxxxxxxxxxxxxxx>
Sent: Tuesday, December 25, 2007 2:21 AM
Subject: Sleep Chemical Central To Effectiveness Of Deep Brain Stimulation


> ScienceDaily (Dec. 24, 2007) â 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."
> The lead authors on the paper are post-doctoral research associate Lane
> Bekar,
> Ph.D., and neurosurgeon Witold Libionka, M.D. The Rochester team is based
> both in the Department of Neurosurgery and the Center for Translational
> Medicine. In addition to Nedergaard and Bakos, other authors from
> Rochester
> include research assistant professors Guo F. Tian and Takahiro Takano;
> graduate students Arnulfo Torres and Ditte Lovatt; technical associate
> Qiwu
> Xu; former post-doctoral research associate Xiaohai Wang; and Erika
> Williams,
> a Fairport native and an undergraduate student at Williams College. Jurgen
> Schnermann of the National Institutes of Health also contributed.
> Adapted from materials provided by University of Rochester Medical Center.
>
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