LOS ANGELES, May 14 (UPI) -- The sleep disorders that accompany Parkinson's disease are caused by the same peptide deficiency found in narcolepsy, say U.S. researchers.
Researchers at the University of California at Los Angeles said the cause of narcolepsy -- characterized by sudden episodes of deep sleep during the day and an inability to sleep at night -- was caused by a loss of the peptide hypocretin, which helps regulate the sleep cycle.
The team found in a study focusing on the brains of Parkinson's patients that people with Parkinson's disease also lost increasing number of hypocretin cells as the disease progressed.
Thus, the researchers recommended that people with Parkinson's disease should receive the same hypocretin replacement therapy given to people with narcolepsy to see if it would reverse the sleep problems associated with Parkinson's disease.
The study is published in the online advance version of the June issue of the journal Brain.
