title: Carbon monoxide may be an important molecule in migraine and other headaches.
abstract: BACKGROUND
  Carbon monoxide was previously considered to just be a toxic gas. A wealth of recent information has, however, shown that it is also an important endogenously produced signalling molecule involved in multiple biological processes. Endogenously produced carbon monoxide may thus play an important role in nociceptive processing and in regulation of cerebral arterial tone.
  
  
  CONCLUSIONS
  Carbon monoxide-induced headache shares many characteristics with migraine and other headaches. The mechanisms whereby carbon monoxide causes headache may include hypoxia, nitric oxide signalling and activation of cyclic guanosine monophosphate pathways. Here, we review the literature about carbon monoxide-induced headache and its possible mechanisms.
  
  
  CONCLUSIONS
  We suggest, for the first time, that carbon monoxide may play an important role in the mechanisms of migraine and other headaches.
authors.affiliation: Danish Headache Center and Department of Neurology, Glostrup Hospital, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
authors.forename: Nanna
authors.initials: N
authors.lastname: Arngrim
authors.affiliation: Danish Headache Center and Department of Neurology, Glostrup Hospital, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
authors.forename: Henrik W
authors.initials: HW
authors.lastname: Schytz
authors.affiliation: Danish Headache Center and Department of Neurology, Glostrup Hospital, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
authors.forename: Mette K
authors.initials: MK
authors.lastname: Hauge
authors.affiliation: Danish Headache Center and Department of Neurology, Glostrup Hospital, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
authors.forename: Messoud
authors.initials: M
authors.lastname: Ashina
authors.affiliation: Danish Headache Center and Department of Neurology, Glostrup Hospital, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark jes.olesen@regionh.dk.
authors.forename: Jes
authors.initials: J
authors.lastname: Olesen
mesh_terms: D000818:Animals; D002248:Carbon Monoxide / Q000378:metabolism*; D006801:Humans; D008881:Migraine Disorders / Q000378:metabolism*
chemical_list: D002248:Carbon Monoxide
keywords: Carbon monoxide; cerebral vessels; haeme oxygenase; headache; pain processing