The neurobiology of vascular head pain

TLDR

Nervous connections between trigeminal ganglia and cerebral blood vessels, known as the trigeminovascular system, have been identified in animals and are inferred to exist in humans. The study examines how trigeminovascular fibers contribute to vascular head pain, informing migraine and other CNS headache conditions. Trigeminovascular neurons contain substance P, which is transported to peripheral fibers and released into cerebral vessel walls upon depolarization. Substance P dilates pial arteries, increases vascular permeability, and activates inflammatory cells.

Abstract

Abstract Nervous connections between the trigeminal ganglia and cerebral blood vessels have recently been identified in experimental animals and have been termed the trigeminovascular system. Existence of this system in humans is inferential. Trigeminovascular neurons and their peripheral unmyelinated nerve fibers contain the neurotransmitter peptide substance P. Most newly synthesized substance P is transported from ganglion cell bodies to afferent nerve fibers, where depolarization‐induced release of neurotransmitter into the wall of the cerebral blood vessel occurs. Substance P dilates pial arteries, increases vascular permeability, and activates cells that participate in the inflammatory response. The relationship of trigeminovascular fibers to the pathogenesis of vascular head pain sheds light on possible mechanisms of migraine and other central nervous system conditions associated with headache and inflammation.