Sleep disorder traced to assault on brain cells
Narcolepsy occurs when wayward immune forces launch an attack on brain cells responsible for wakefulness, a new study suggests. In a case of mistaken identity, immune cells that target a protein fragment from a microbial invader also on rare occasions ravage neurons that produce a similar protein fragment, or peptide, researchers report.
The victims of this cross fire are neurons that make a peptide called orexin, a neurotransmitter that is crucial for staying awake. The researchers say this could explain the lack of orexin neurons in people with narcolepsy, as shown previously in patient autopsies. A lack of orexin, also called hypocretin, leaves a person with disordered sleep, daytime drowsiness and the risk of nodding off abruptly — the hallmarks of narcolepsy.
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