Electrical stimulation of the Gasserian ganglion induces structural alterations of calcitonin gene-related peptide-immunoreactive perivascular sensory nerve terminals in the rat cerebral dura mater: a possible model of migraine headache

Although it is known that pain in the forehead may be induced by neck abnormalities, the actual neck-head connections responsible for development of pain in trigeminal areas are poorly understood. Vasoactive neuropeptides released from sensory fibres, such as substance P (SP) and calcitonin gene-related peptide (CGRP), have been considered as important elements in headache pathophysiology. The levels of CGRP-like immunoreactivity (LI) were measured bilaterally in the jugular blood (52 rats) and intraocular aspirates (66 rats) following electrical stimulation of the left greater occipital nerve, and in the jugular blood of 13 control animals. One-third of the stimulated rats had varying combinations of conjunctival injection, tearing, diminished eye aperture and miosis or mydriasis on the stimulated side. The other two-thirds exhibited no ocular signs. Significantly lower levels of CGRP-LI were present in the jugular blood on the stimulated side in comparison with control rats. There was comparatively lower CGRP-LI on the non-stimulated side as well, but to a lesser extent. Significant differences between the stimulated and the non-stimulated side were present, particularly in the tearing/diminished eye cleft group. It is proposed that stimulation of the rat GON inhibits the trigeminal system (reduction of CGRP-LI) and possibly activates parasympathetic fibres (ocular changes).

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Alterations in neurokinin A-, substance P- and calcitonin gene-related peptide immunoreactivities in the caudal trigeminal nucleus of the rat following electrical stimulation of the trigeminal ganglion

Neuroscience Letters ◽

10.1016/s0304-3940(98)00989-6 ◽

1999 ◽

Vol 261 (3) ◽

pp. 179-182 ◽

Cited By ~ 18

Author(s):

M. Samsam ◽

R. Coveñas ◽

R. Ahangari ◽

J. Yajeya ◽

J.A. Narváez ◽

...

Keyword(s):

Electrical Stimulation ◽

Substance P ◽

Trigeminal Ganglion ◽

Calcitonin Gene Related Peptide ◽

Neurokinin A ◽

Trigeminal Nucleus ◽

Related Peptide ◽

Calcitonin Gene ◽

Caudal Trigeminal Nucleus ◽

Stimulation Of

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Calcitonin gene related peptide released from dural nerve fibers mediates increase of meningeal blood flow in the rat

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y95-143 ◽

1995 ◽

Vol 73 (7) ◽

pp. 1020-1024 ◽

Cited By ~ 52

Author(s):

K. Meßlinger ◽

U. Hanesch ◽

M. Kurosawa ◽

M. Pawlak ◽

R. F. Schmidt

Keyword(s):

Blood Flow ◽

Dura Mater ◽

Calcitonin Gene Related Peptide ◽

Nerve Fibers ◽

Dura Mater Encephali ◽

Related Peptide ◽

Calcitonin Gene ◽

Meningeal Blood Flow ◽

Meningeal Artery ◽

Stimulation Of

The parietal dura mater encephali of the rat was shown by immunohistochemistry to be densely innervated by calcitonin gene related peptide (CGRP) immunoreactive nerve fibers spreading around the medial meningeal artery and its branches. Electrical stimulation of the dural surface (10–20 V, 5–10 Hz, 10–30 min) caused a depletion of CGRP-immunopositive fibers, suggesting a release of CGRP. The dural blood flow around branches of the medial meningeal artery was also monitored with a laser Doppler flowmeter. Short periods (30 s) of electrical stimulation with parameters that presumably released CGRP from nerve fibers caused a repeatable and constant increase of the blood flow for 1–2 min. This evoked increase could dose dependently be inhibited by topical application of the CGRP antagonist hCGRP8–37. Accordingly, administration of hCGRP increased the basal blood flow. We conclude that stimulation of trigeminal afferents innervating the dura mater releases CGRP from peptidergic afferent terminals, thereby causing vasodilatation and increasing the meningeal blood flow, an important element of neurogenic inflammation.Key words: dura mater encephali, afferent nerve fibers, calcitonin gene related peptide, immunohistochemistry, laser Doppler flowmetry.

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