title: Calcitonin Gene-Related Peptide Modulates Heat Nociception in the Human Brain - An fMRI Study in Healthy Volunteers.
abstract: BACKGROUND
  Intravenous infusion of calcitonin-gene-related-peptide (CGRP) provokes headache and migraine in humans. Mechanisms underlying CGRP-induced headache are not fully clarified and it is unknown to what extent CGRP modulates nociceptive processing in the brain. To elucidate this we recorded blood-oxygenation-level-dependent (BOLD) signals in the brain by functional MRI after infusion of CGRP in a double-blind placebo-controlled crossover study of 27 healthy volunteers. BOLD-signals were recorded in response to noxious heat stimuli in the V1-area of the trigeminal nerve. In addition, we measured BOLD-signals after injection of sumatriptan (5-HT1B/1D antagonist).
  
  
  RESULTS
  Brain activation to noxious heat stimuli following CGRP infusion compared to baseline resulted in increased BOLD-signal in insula and brainstem, and decreased BOLD-signal in the caudate nuclei, thalamus and cingulate cortex. Sumatriptan injection reversed these changes.
  
  
  CONCLUSIONS
  The changes in BOLD-signals in the brain after CGRP infusion suggests that systemic CGRP modulates nociceptive transmission in the trigeminal pain pathways in response to noxious heat stimuli.
authors.affiliation: Danish Headache Center and Department of Neurology, Glostrup Hospital, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2600, Glostrup, Denmark.
authors.forename: Mohammad Sohail
authors.initials: MS
authors.lastname: Asghar
authors.affiliation: P.A.I.N. Group, Boston Children's Hospital and Center for Pain and the Brain, Harvard Medical School, Boston, Massachusetts, 02453, United States of America.
authors.forename: Lino
authors.initials: L
authors.lastname: Becerra
authors.affiliation: Functional Imaging Unit, Department of Diagnostic, Glostrup Hospital, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2600, Glostrup, Denmark.
authors.forename: Henrik B W
authors.initials: HB
authors.lastname: Larsson
authors.affiliation: P.A.I.N. Group, Boston Children's Hospital and Center for Pain and the Brain, Harvard Medical School, Boston, Massachusetts, 02453, United States of America.
authors.forename: David
authors.initials: D
authors.lastname: Borsook
authors.affiliation: Danish Headache Center and Department of Neurology, Glostrup Hospital, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2600, Glostrup, Denmark.
authors.forename: Messoud
authors.initials: M
authors.lastname: Ashina
mesh_terms: D000328:Adult; D001921:Brain / Q000187:drug effects* / Q000502:physiology; D015740:Calcitonin Gene-Related Peptide / Q000494:pharmacology*; D005260:Female; D064368:Healthy Volunteers; D006358:Hot Temperature; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D059225:Nociception; D010919:Placebos; D055815:Young Adult
chemical_list: D010919:Placebos; D015740:Calcitonin Gene-Related Peptide