Phenotypic alterations of neuropeptide Y and calcitonin gene-related peptide-containing neurons innervating the rat temporomandibular joint during carrageenan-induced arthritis

Abstract

The aim of this study was to identify immunoreactive neuropeptide Y (NPY) and calcitonin gene-related peptide (CGRP) neurons in the autonomic and sensory ganglia, specifically neurons that innervate the rat temporomandibular joint (TMJ). A possible variation between the percentages of these neurons in acute and chronic phases of carrageenan-induced arthritis was examined. Retrograde neuronal tracing was combined with indirect immunofluorescence to identify NPY-immunoreactive (NPY-IR) and CGRP- immunoreactive (CGRP-IR) neurons that send nerve fibers to the normal and arthritic temporomandibular joint. In normal joints, NPY-IR neurons constitute 78±3%, 77±6% and 10±4% of double-labeled nucleated neuronal profile originated from the superior cervical, stellate and otic ganglia, respectively. These percentages in the sympathetic ganglia were significantly decreased in acute (58±2% for superior cervical ganglion and 58±8% for stellate ganglion) and chronic (60±2% for superior cervical ganglion and 59±15% for stellate ganglion) phases of arthritis, while in the otic ganglion these percentages were significantly increased to 19±5% and 13±3%, respectively. In the trigeminal ganglion, CGRP-IR neurons innervating the joint significantly increased from 31±3% in normal animals to 54±2% and 49±3% in the acute and chronic phases of arthritis, respectively. It can be concluded that NPY neurons that send nerve fibers to the rat temporomandibular joint are located mainly in the superior cervical, stellate and otic ganglia. Acute and chronic phases of carrageenan-induced arthritis lead to an increase in the percentage of NPY-IR parasympathetic and CGRP-IR sensory neurons and to a decrease in the percentage of NPY-IR sympathetic neurons related to TMJ innervation.

Evaluation of Plasma Calcitonin Gene-Related Peptide as a Biomarker for Painful Temporomandibular Disorder and Migraine

“… 58 Establishing CGRP involvement in arthrogenous TMD, an increased number of TMJ-innervating CGRP-immunoreactive neurons was detected in the rat trigeminal ganglion in a carrageenan-induced TMJ arthritis model. 59 The elevated CGRP level in the trigeminal ganglion and spinal trigeminal nucleus was also confirmed in another model of TMJ arthritis in rats. 60 Additionally, injecting CGRP in the rat TMJ stimulated neuronal and glial expression of proteins involved in the development of peripheral and central sensitization.…”

Comparison of CGRP distributions in the maxillary sinus and trigeminal ganglion between elderly dentulous and edentulous humans

“…In the TG, the CGRP-IR neurons that innervated the joint were significantly increased compared to those in normal animals in the acute and chronic phases of arthritis, respectively. 35 That is, tooth stress may reflect the release of CGRP from the sensory nerve terminals of the MS by the human TG in the same manner. 12 Therefore, the anti-CGRP reaction was decreased in the alveolar bone of the edentulous group compared to the dentulous group.…”

Impact of Histochemistry on biomedical research: looking through the articles published in a long-established histochemical journal

“…Immunohistochemical techniques were recently used to describe the topographical distribution of nerve cell populations in vertebrate and invertebrate species, 47-51 and to investigate the effects of aging or experimentally-induced stress on the central nervous system. 52-56 The maturation and elimination of oocytes was studied in mammals, 57-59 while specific proteins were investigated during the pre- and neo-natal development, 60-72 in particular of kidney 60 , 61 and heart. 62 , 63 Descriptive articles have also been published on the expression of different molecules in Vertebrates organs.…”