title: Differential TRPV1 and TRPV2 channel expression in dental pulp.
abstract: Hypersensitivity to thermal and mechanical stimuli can occur in painful pulpitis. To explore the neuro-anatomical basis of heat and mechanical sensitivity, we evaluated expression of TRPV1 (heat) and TRPV2 (heat/mechanical) channels in the cell bodies and terminal arborizations of neurons that innervate the dental pulp (DP) and periodontal tissues (PDL). We report that ~50% of trigeminal ganglion (TG) neurons retrogradely labeled from the DP express TRPV2, and this was significantly greater than the general expression of this channel in the TG (15%) and slightly more than what is expressed in the PDL by retrograde labeling (40%). The TRPV1 receptor, however, was less prevalent in neurons innervating the DP than their general expression in the TG (17% vs. 26%) and was more extensively expressed in neurons innervating the PDL (26%). Co-labeling studies showed that 70% of neurons that innervate the DP are myelinated. Approximately 1/3 of the retrogradely labeled neurons from the DP were calcitonin-gene-related-peptide-positive (peptide-expressing), but very few expressed the IB4 marker of non-peptidergic unmyelinated afferents. These findings suggest that the DP has a unique neurochemical innervation with regard to TRP receptor expression, which has significant implications for the mechanisms contributing to odontogenic pain and management strategies.
authors.affiliation: Department of Preventive and Restorative Dental Sciences, University of California San Francisco, CA 94158, USA. jlg15@nyu.edu
authors.forename: J L
authors.initials: JL
authors.lastname: Gibbs
authors.forename: J L
authors.initials: JL
authors.lastname: Melnyk
authors.forename: A I
authors.initials: AI
authors.lastname: Basbaum
mesh_terms: D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000096:biosynthesis; D003782:Dental Pulp / Q000294:innervation* / Q000378:metabolism; D005456:Fluorescent Dyes; D006358:Hot Temperature; D008297:Male; D040542:Mechanotransduction, Cellular / Q000502:physiology; D009619:Nociceptors / Q000378:metabolism*; D010513:Periodontal Ligament / Q000294:innervation* / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013266:Stilbamidines; D050916:TRPV Cation Channels / Q000096:biosynthesis*; D012668:Trigeminal Ganglion / Q000166:cytology / Q000378:metabolism*
chemical_list: C049774:2-hydroxy-4,4'-diamidinostilbene, methanesulfonate salt; D005456:Fluorescent Dyes; D013266:Stilbamidines; D050916:TRPV Cation Channels; C493922:Trpv1 protein, rat; C476722:Trpv2 protein, rat; D015740:Calcitonin Gene-Related Peptide