title: Vessel diameter measurements at the medullary brainstem in vivo as an index of trigeminal activity.
abstract: Activity within the CNS can be quantified by a variety of methods. Here, we present an indirect method utilizing the neuro-vascular coupling via a continuous measurement of the vessel diameter. In anaesthetized rats, induced neuronal activity in the trigeminal system could be detected via arterial diameter measurements at the back of the medullary brainstem. Building upon the previously described diameter plugin, in images aligned to compensate for ventilation and heart-rate associated movement, automated processing allowed an evaluation immediately after acquisition. Electrical stimulation of facial trigeminal areas or the cranial dura mater caused vasodilatation of arteries in the dorsal medullary brainstem, which was abolished after application of the CGRP receptor antagonist olcegepant. No change in diameter was observed in corresponding veins. Intravenous infusion of sodium sulfide, which induces nitroxyl formation, also induced vasodilatation of brainstem-supplying arteries. Both experiments show a functional role of CGRP in the trigeminal nuclear brainstem complex. The presented method allows estimating central activity at the spinal level by vascular responses.
authors.affiliation: Institute of Physiology and Pathophysiology, University of Erlangen-Nürnberg, Erlangen, Germany.
authors.forename: Christine
authors.initials: C
authors.lastname: Will
authors.affiliation: Institute of Physiology and Pathophysiology, University of Erlangen-Nürnberg, Erlangen, Germany.
authors.forename: Karl
authors.initials: K
authors.lastname: Messlinger
authors.affiliation: Institute of Physiology and Pathophysiology, University of Erlangen-Nürnberg, Erlangen, Germany. Electronic address: fischer@physiologie1.uni-erlangen.de.
authors.forename: Michael J M
authors.initials: MJ
authors.lastname: Fischer
mesh_terms: D000818:Animals; D001808:Blood Vessels / Q000187:drug effects / Q000502:physiology; D001933:Brain Stem / Q000098:blood supply / Q000187:drug effects / Q000502:physiology; D005260:Female; D008297:Male; D008526:Medulla Oblongata / Q000098:blood supply* / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D013440:Sulfides / Q000494:pharmacology; D014278:Trigeminal Nuclei / Q000098:blood supply* / Q000187:drug effects / Q000502:physiology*; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology*
chemical_list: D013440:Sulfides; C033479:sodium sulfide
keywords: Brainstem; Migraine; Neuronal correlates; Neurovascular coupling; Trigeminal