Normal plasma levels of orexin A (hypocretin-1) in narcoleptic patients

Neurology. 2001 Jun 26;56(12):1749-51. doi: 10.1212/wnl.56.12.1749.


Deficient orexin signaling has been shown to cause narcolepsy-like conditions in animals. In human narcolepsy, CSF levels of orexin A (hypocretin-1) were reported to be low in most cases. The authors measured CSF and plasma orexin A levels in patients with narcolepsy and in controls. Confirming earlier studies, they found CSF orexin A levels to be extremely low in patients with narcolepsy. However, plasma orexin A levels did not differ from those observed in controls. These results suggest that orexin deficiency in patients with narcolepsy is a phenomena restricted to the CNS.

MeSH terms

  • Adult
  • Carrier Proteins / blood*
  • Carrier Proteins / cerebrospinal fluid*
  • Female
  • Humans
  • Intracellular Signaling Peptides and Proteins*
  • Male
  • Middle Aged
  • Narcolepsy / blood*
  • Narcolepsy / cerebrospinal fluid*
  • Neuropeptides / blood*
  • Neuropeptides / cerebrospinal fluid*
  • Orexins
  • Radioimmunoassay


  • Carrier Proteins
  • HCRT protein, human
  • Intracellular Signaling Peptides and Proteins
  • Neuropeptides
  • Orexins