Normal cerebrospinal fluid levels of hypocretin-1 (orexin A) in patients 
with fibromyalgia syndrome.

Sleep Med. 2007 Mar 16; [Epub ahead of print]

Taiwo OB, Russell IJ, Mignot E, Lin L, Michalek JE, Haynes W, Xiao Y, 
Zeitzer JM, Larson AA.

University of Minnesota, Department of Veterinary and Biomedical Sciences, 
Rm 295, Animal Science/Veterinary Medicine Building, 1988 Fitch Avenue, St. 
Paul, MN 55113, USA.

PMID: 17369087


BACKGROUND: The hypothalamic neuropeptide hypocretin (orexin) modulates 
sleep-wake, feeding and endocrine functions. Cerebrospinal fluid (CSF) 
hypocretin-1 (Hcrt-1) concentrations are low in patients with 
narcolepsy-cataplexy, a sleep disorder characterized by hypersomnolence and 
rapid eye movement (REM) sleep abnormalities.

METHODS: We determined CSF Hcrt-1 concentrations of patients with the 
fibromyalgia syndrome (FMS), a condition characterized by fatigue, insomnia 
and in some cases daytime hypersomnolence.

RESULTS: Basal CSF levels of Hcrt-1 in FMS did not differ from those in 
healthy normal controls.

CONCLUSIONS: These findings suggest that abnormally low Hcrt-1 is not a 
likely cause of fatigue in FMS.