Neurogenic inflammation is one of the factors implicated in the pathogenesis of several neurological diseases, such as migraine. The nociceptive innervation of the intracranial vascular system and meninges consists of unmyelinated (C fibers) and thinly myelinated (Ad fibers) axons containing vasoactive peptides, such as calcitonin gene-related peptide (CGRP), substance P, and neurokinin A. Nociceptive transmission originates from the trigeminal ganglion to the brain stem and subsequently second-order sensitive neurons, including the trigeminal spinal nucleus. In turn, third-order neurons in the thalamus are activated, and nociception reaches the somatosensory cortex as well as other cortical areas. Almost all cranial tissues, including the intracranial and extracranial structures of the head and face, are innervated by trigeminal afferents. View this paper