Distribution and possible function of galanin about headache and immune system in the rat dura mater

Abstract

Galanin (GAL) is a nociceptive transmitter or modulator in the trigeminal sensory system. In this study, GAL expression was investigated in the rat dura mater to demonstrate its possible function in headache using immunohistochemical techniques. The cerebral falx and cerebellar dura mater received abundant blood and nerve supply, and were significantly thicker compared to other portions in the cerebral dura mater. GAL-immunoreactivity was expressed by cell and nerve fiber profiles. Presumed macrophages and dendritic cells contained GAL-immunoreactivity, and co-expressed with CD11b-immunoreactivity. Many isolated and perivascular nerve fibers also showed GAL-immunoreactivity. In addition, GAL-immunoreactive nerve fibers were present in the vicinity of macrophages and dendritic cells with either GAL- or ED1-immunoreactivity. GAL-immunoreactive cells and nerve fibers were common in the cerebral falx and cerebellar dura mater and infrequent in other portions. And, GAL-immunoreactive nerve fibers usually co-expressed calcitonin gene-related peptide (CGRP)-immunoreactivity. In the trigeminal ganglion, a substantial proportion of sensory neurons innervating the dura mater contained GAL-immunoreactivity (mean ± SD, 3.4 ± 2.2%), and co-expressed CGRP-immunoreactivity (2.7 ± 2.1%). The present study may suggest that GAL is associated with nociceptive transduction or modulation in the dura mater. GAL also possibly plays a role in the immune mechanism of the dura mater.

Role of neuropeptides in orofacial pain: A literature review

“…On the other hand, GAL can also act directly on various immune inflammatory cells, inhibiting the expression of pro‐inflammatory cytokines. GAL‐IR nerve fibres are present in the vicinity of macrophages and dendritic cells with GAL‐immunoreactivity 53 . GAL can regulate the expression of some chemokines, transforming growth factor β (TGF‐β), IL, and TNF‐α in macrophages, and also make NK cells sensitive to specific cytokines, thus participating in the regulation of the immune‐inflammatory process 53 .…”

“…GAL‐IR nerve fibres are present in the vicinity of macrophages and dendritic cells with GAL‐immunoreactivity 53 . GAL can regulate the expression of some chemokines, transforming growth factor β (TGF‐β), IL, and TNF‐α in macrophages, and also make NK cells sensitive to specific cytokines, thus participating in the regulation of the immune‐inflammatory process 53 . The anti‐inflammatory effect of GAL may exert an indirect facilitating effect on its analgesic effect.…”

Anatomy and Physiology of Headache

“…Others with emerging roles in pain transmission include cholecystokinin, galanin, enkephalins, nociceptin, growth-associated protein 43, and angiotensin II. 20,[23][24][25] The role of CGRP in headache disorders is now well established. Dural afferents contain the canonical CGRP receptor and the structurally related receptors for amylin and adrenomedullin.…”

“…Others with emerging roles in pain transmission include cholecystokinin, galanin, enkephalins, nociceptin, growth-associated protein 43, and angiotensin II. 20 23 24 25…”

Characterization of Headache in Patients with Temporomandibular Joint Disorders

“…Animal studies, as well as human imaging studies, have stressed the importance of sterile dural inflammation as a universal finding in primary headaches; thereby sensitizing the receptors [7,8]. The dural inflammation is associated with an increased barrage of action potentials, along nociceptive fibers to the trigeminal ganglion [9,10]. Furthermore, non-trigeminal nociceptive afferents from the occipital dura mater and cervical structures contribute to headaches; being mediated through the upper three cervical nerves [11,12].…”