New Insights on Anxiety, Sleep Disorders
Newly Discovered Brain Protein Plays Key Role
Aug. 18, 2004 -- Millions of people are affected by anxiety and sleep
disorders. Now, researchers may be one step closer to understanding -- and
eventually resolving -- these complicated conditions after studying a newly
discovered brain protein.
The protein is called neuropeptide S, and it "potently
modulates wakefulness and could also regulate anxiety," say researchers
from the University of California Irvine and the Scripps Research Institute in
La Jolla, Calif.
They published their findings in the journal Neuron.
In the study, researchers find that injections of neuropeptide
S in mice and rats not only increase physical
activity and wakefulness, but can also decrease the duration of rapid eye
movement (REM) and slow-wave sleep.
During REM sleep there are increases in brain activity and eye
movement, yet muscles are relaxed. This stage of sleep is associated with
intense dreaming. Slow-wave sleep is also a deep sleep stage.
"The effects of [neuropeptide S] on inducing wakefulness
are rapid [during the first hour after injection] and potent, since low doses
of [neuropeptide S] are sufficient to reduce all sleep stages ... suggesting a
profound change in sleep architecture," write the authors.
The protein was found to be produced in parts of the brain
known to regulate arousal and anxiety, in a cluster of previously unidentified
cells. The protein seemed to function in areas of the brain related to stress.
The study also showed that mice that received neuropeptide-S
injections showed less anxiety-associated behavior in four different stressful
The discovery "might help to further our understanding of
sleep disorders, such as insomnia and pathological states of anxiety," write
Rainer Reinscheid, PhD, assistant adjunct pharmacology professor at the
University of California Irvine, and colleagues.
"We may be at the tip of the iceberg" in understanding
neuropeptide S, says Reinscheid, in a news release. Eventually, treatments for
sleep and anxiety problems could result from work on the brain protein.
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