Reduction of Calcitonin Gene-Related Peptide in Jugular Blood Following Electrical Stimulation of Rat Greater Occipital Nerve

Abstract

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).

Occipital Nerve Stimulation for Headache Disorders

“…There is some animal evidence to support this notion, as stimulation of the greater occipital nerve in the rat reduces calcitonin gene-related peptide in the jugular blood, which is a biomarker of inhibition of the trigeminal system. 36 A functional imaging study in chronic migraine patients supports the notion that ONS may influence supraspinal structures involved in central nociceptive trafficking, such as the dorsal rostral pons, the pulvinar nucleus of the thalamus and the anterior cingulate cortex. 12 More details on the possible mechanism(s) of action, especially on the TCC, have been covered elsewhere.…”

Headache Plus: Trigeminal and Autonomic Features in a Case of Cervicogenic Headache Responsive to Third Occipital Nerve Radiofrequency Ablation: Table 1

“…While the TACs are felt to originate in the hypothalamic–pituitary axis [13,14], the spinal trigeminocervical complex implicated in cervicogenic headache would seem less likely to cause direct hypothalamic disturbance or pericarotid parasympathetic overactivity. The convergence of spinal and trigeminal afferents in the spinal trigeminocervical complex may also indirectly activate the superior salivatory nucleus mediating parasympathetic activity [15] as experimental stimulation of the greater occipital nerve branch of C2 has resulted in ipsilateral tearing, ptosis, and conjunctival injection in rats [16]; however, the potential anatomical connections for these effects are less clear. Alternatively, the trigeminal‐distribution edema seen in cervicogenic headache could be due to neurogenic inflammation, whereby the stimulation of primary trigeminal nociceptive central terminals causes antidromic propagation in the trigeminal first‐order nociceptors, peripheral release of neuropeptides calcitonin gene‐related peptide and substance P, and subsequent vasodilation and increased capillary permeability [17,18].…”

Headache Research and Medical Practice in Brazil: An Historical Overview

“…In Rio de Janeiro, São Paulo, Paraná, Santa Catarina, and Rio Grande do Sul, there are several centers dealing with headache disorders and an excellent scientific production has been made by a number of headache specialists, mentioning Abouch Krymchantowski, Carla da Cunha Jevoux, Maurice Vincent, Pedro Ferreira Moreira Filho, Jano Alves de Souza, Maria Eduarda Nobre in Rio de Janeiro; Celia P. Roesler, Deusvenir de Souza Carvalho, Eliova Zukerman, Mario Fernando Prieto Peres,…”

“…In Rio de Janeiro, São Paulo, Paraná, Santa Catarina, and Rio Grande do Sul, there are several centers dealing with headache disorders and an excellent scientific production has been made by a number of headache specialists, mentioning Abouch Krymchantowski, [217][218][219][220][221][222][223][224][225][226]234,287,[350][351][352][353][354][355] Carla da Cunha Jevoux, 46,204,213,214,223,224,264,265,293,[296][297][298]300,302,303,356 Maurice Vincent, [93][94][95][96][97][98]101,102,104,189,[274][275][276][277]…”