Health Watch -- Treating Narcolepsy

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A new discovery could lead to treatments for two seemingly opposite problems.

Narcolepsy is a rare disease that causes people to fall asleep uncontrollably and feel excessively sleepy during the day. People with this disease may also have bouts of sudden muscle weakness. Researchers at UT Southwestern Medical Center at Dallas have discovered a possible treatment for this disease and insomnia, which keeps people from getting to sleep or staying asleep at night.

Scientists believe that a deficiency in a brain chemical called orexin causes narcolepsy. The UT Southwestern researchers found that injecting this chemical into mice that don't adequately produce it on their own eased the symptoms of narcolepsy. The treatment helped mice stay awake, and they didn't appear to try to make it up with extra sleep once the chemical wore off. The treatment also helped prevent the bouts of muscle weakness associated with narcolepsy.

Dr. Masashi Yanagisawa, the UT Southwestern molecular geneticist who led this study, says he believes this mechanism would work in a similar way in humans with narcolepsy. Treatments for narcolepsy developed from this research will involve finding molecules that mimic the effect of orexin that are small enough to cross from the bloodstream into the brain.

This same treatment could also help patients with a seemingly opposite problem. People with insomnia, who often don't get enough sleep at night, are often sleepy during the day. This treatment could help prevent that daytime sleepiness.


April 2004