title: Expression of ecto-ATPase NTPDase2 in human dental pulp.
abstract: Dental pulpal nerve fibers express ionotropic adenosine triphosphate (ATP) receptors, suggesting that ATP signaling participates in the process of dental nociception. In this study, we investigated if the principal enzymes responsible for extracellular ATP hydrolysis, namely, nucleoside triphosphate diphosphohydrolases (NTPDases), are present in human dental pulp. Immunohistochemical and immunofluorescence experiments showed that NTPDase2 was predominantly expressed in pulpal nerve bundles, Raschkow's nerve plexus, and in the odontoblast layer. NTPDase2 was expressed in pulpal Schwann cells, with processes accompanying the nerve fibers and projecting into the odontoblast layer. Odontoblasts expressed the gap junction protein, connexin43, which can form transmembrane hemichannels for ATP release. NTPDase2 was localized close to connexin43 within the odontoblast layer. These findings provide evidence for the existence of an apparatus for ATP release and degradation in human dental pulp, consistent with the involvement of ATP signaling in the process of dentin sensitivity and dental pain.
authors.affiliation: Division of General Dentistry, University of Rochester Eastman Institute for Oral Health, 625 Elmwood Avenue, Rochester, NY 14620, USA.
authors.forename: X
authors.initials: X
authors.lastname: Liu
authors.forename: L
authors.initials: L
authors.lastname: Yu
authors.forename: Q
authors.initials: Q
authors.lastname: Wang
authors.forename: J
authors.initials: J
authors.lastname: Pelletier
authors.forename: M
authors.initials: M
authors.lastname: Fausther
authors.forename: J
authors.initials: J
authors.lastname: Sévigny
authors.forename: H S
authors.initials: HS
authors.lastname: Malmström
authors.forename: R T
authors.initials: RT
authors.lastname: Dirksen
authors.forename: Y F
authors.initials: YF
authors.lastname: Ren
mesh_terms: D000251:Adenosine Triphosphatases / Q000096:biosynthesis* / Q000502:physiology; D018031:Connexin 43 / Q000096:biosynthesis*; D003782:Dental Pulp / Q000166:cytology / Q000201:enzymology* / Q000294:innervation; D003807:Dentin Sensitivity / Q000209:etiology* / Q000378:metabolism; D006801:Humans; D008964:Molar, Third; D009804:Odontoblasts / Q000201:enzymology / Q000378:metabolism; D012583:Schwann Cells / Q000201:enzymology; D015398:Signal Transduction; D014098:Toothache / Q000209:etiology* / Q000378:metabolism; D014746:Vimentin / Q000096:biosynthesis
chemical_list: D018031:Connexin 43; D014746:Vimentin; D000251:Adenosine Triphosphatases; C027201:ectoATPase