UCLA researchers find new clue to cause of human narcolepsy

In 2000, researchers at the UCLA Center for Sleep Research published findings showing that people suffering from narcolepsy, a disorder characterized by uncontrollable periods of deep sleep, had 90 percent fewer neurons containing the neuropeptide hypocretin in their brains than healthy people. The study was the first to show a possible biological cause of the disorder.   Subsequent work by this group and others demonstrated that hypocretin is an arousing chemical that keeps us awake and elevates both mood and alertness; the death of hypocretin cells, the researchers said, helps explain the sleepiness of narcolepsy. But it has remained unclear what kills these cells.    Now the same UCLA team reports that an excess of another brain cell type — this one containing histamine — may be the cause of the loss of hypocretin cells in human narcoleptics.    UCLA professor of psychiatry Jerome Siegel and colleagues report in the current online edition of the journal Annals of Neurology that people with the disorder have nearly 65 percent more brain cells containing the chemical histamine. Their research suggests that this excess of histamine cells causes the loss of hypocretin cells in human narcoleptics.   Narcolepsy is a chronic disorder of the central nervous system characterized by the brain's inability to control sleep–wake cycles. It causes sudden bouts of sleep and is often accompanied by cataplexy, an abrupt loss of voluntary musc...
Source: UCLA Newsroom: Health Sciences - Category: Universities & Medical Training Source Type: news