title: Parvalbumin- and calretinin-immunoreactive trigeminal neurons innervating the rat molar tooth pulp.
abstract: Calcium-binding proteins and neuropeptides were examined in trigeminal neuronal cell bodies retrogradely labeled with Fast blue (FB) from the maxillary molar tooth pulp of the rat. FB-labeled cells were located in the maxillary division of the trigeminal ganglion. Approximately 30 and 50% of the labeled cells were immunoreactive for parvalbumin and calcitonin gene-related peptide (CGRP), respectively. The coexpression of these substances was observed in 9.5% of FB-labeled cells. On the other hand, 2.4% of FB-labeled cells exhibited calretinin-immunoreactivity (CR-ir) and 20% tachykinin (TK)-ir. The coexpression of CR and TK was observed in 1.9% of FB-labeled cells, i.e., most of CR-ir FB-labeled neurons coexpressed TK-ir. An immuno-EM method revealed that all parvalbumin-ir nerve fibers in the root pulp were myelinated and that CGRP-ir nerve fibers were both myelinated (15%) and unmyelinated (85%). The present study indicated that primary nociceptors innervating the rat molar tooth pulp contained parvalbumin and CR and coexpressed these calcium-binding proteins and neuropeptides. It was suggested that peripheral axons of parvalbumin-ir tooth pulp primary neurons are all myelinated. Most peripheral CR-ir axons are probably unmyelinated because TK-ir myelinated axons have never been demonstrated in any peripheral organ.
authors.affiliation: Department of Orthodontics, Okayama University Dental School, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Ichikawa
authors.forename: T
authors.initials: T
authors.lastname: Deguchi
authors.forename: T
authors.initials: T
authors.lastname: Nakago
authors.forename: D M
authors.initials: DM
authors.lastname: Jacobowitz
authors.forename: T
authors.initials: T
authors.lastname: Sugimoto
mesh_terms: D000818:Animals; D064032:Calbindin 2; D007150:Immunohistochemistry; D008297:Male; D008854:Microscopy, Electron; D009474:Neurons / Q000166:cytology / Q000276:immunology; D010320:Parvalbumins / Q000276:immunology / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D064030:S100 Calcium Binding Protein G / Q000276:immunology / Q000378:metabolism*; D014070:Tooth / Q000276:immunology / Q000294:innervation* / Q000648:ultrastructure; D014276:Trigeminal Nerve / Q000166:cytology* / Q000276:immunology / Q000378:metabolism
chemical_list: C576512:Calb2 protein, rat; D064032:Calbindin 2; D010320:Parvalbumins; D064030:S100 Calcium Binding Protein G