Innervation of the human middle meningeal artery: immunohistochemistry, ultrastructure, and role of endothelium for vasomotility

Neurobiology in primary headaches

“…Furthermore, immunoelectron microscopic studies revealed that, in the human superficial temporal artery, VIP immunoreactivity is localized exclusively to large electron-dense secretory vesicles (diameter 70-100 nm) in nerve terminal varicosities which also contain numerous smaller sized agranular vesicles (diameter 40-60 nm) presumed to represent parasympathetic cholinergic neurons [50]. It should be noted, however, that other studies on the cholinergic and VIPergic cerebrovascular innervation have demonstrated that ChAT and VIP immunoreactivities are co-localised in less than 5% of the fibers examined [138].…”

“…of all nerve cell bodies contain CGRP and CGRP mRNA [50,187]. CGRP and SP are potent vasodilators in vivo and in vitro, the former being 10-1000 times more potent [45,58,59,106,136].…”

“…This results in a decrease in the local intracellular Ca ++ level, giving rise to vasodilatation which may activate the pain sensitive structures around the cranial vessels [148]. Few trigeminal neurones express NOS in laboratory animals [47,50,143]. In human trigeminal ganglia about 15% of the cell bodies contain NOS [187].…”

“…In laboratory animals, the sensory pathway has no resting tonic influence on regional cerebral blood flow or regional cerebral metabolism [58,136] whereas stimulation of the trigeminal ganglion increases intracranial blood flow in part via CGRP release [50,60,81]. In humans, unilateral stimulation of the trigeminal ganglion results in increased bilateral cortical blood flow, slightly more on the stimulated than on the contralateral site [190].…”

Neuropeptide Effects in the Trigeminal System: Pathophysiology and Clinical Relevance in Migraine

“…8,13 Ramifications of the middle meningeal artery as well as the meningeal sinuses are densely innervated by CGRP-immunoreactive nerve fibers, whereas innervation with substance P-immunoreactive fibers is comparably sparse. 14 Although terminals of immunopositive nerve fibers are found everywhere in the dura, it is noticeable that single CGRP-immunopositive nerve fibers run tightly along arterial and precapillary vessels, suggesting a vascular function.…”