title: Odontoblasts in developing, mature and ageing rat teeth have multiple phenotypes that variably express all nine voltage-gated sodium channels.
abstract: OBJECTIVE
  Our goal was to evaluate the expression patterns for voltage gated sodium channels in odontoblasts of developing and mature rat teeth.
  
  
  METHODS
  We analysed immunoreactivity (IR) of the alpha subunit for all nine voltage gated sodium channels (Nav1.1-1.9) in teeth of immature (4 weeks), young adult (7 weeks), fully mature adult (3 months), and old rats (6-12 months). We were interested in developmental changes, crown/root differences, tetrodotoxin sensitivity or resistance, co-localization with nerve regions, occurrence in periodontium, and coincidence with other expression patterns by odontoblasts such as for transient receptor potential A1 (TRPA1).
  
  
  RESULTS
  We found that Nav1.1-1.9-IR each had unique odontoblast patterns in mature molars that all differed from developmental stages and from incisors. Nav1.4- and Nav1.7-IR were intense in immature odontoblasts, becoming limited to specific zones in adults. Crown odontoblasts lost Nav1.7-IR and gained Nav1.8-IR where dentine became innervated. Odontoblast staining for Nav1.1- and Nav1.5-IR increased in crown with age but decreased in roots. Nav1.9-IR was especially intense in regularly scattered odontoblasts. Two tetrodotoxin-resistant isoforms (Nav1.5, Nav1.8) had strong expression in odontoblasts near dentinal innervation zones. Nav1.6-IR was concentrated at intercusp and cervical odontoblasts in adults as was TRPA1-IR. Nav1.3-IR gradually became intense in all odontoblasts during development except where dentinal innervation was dense.
  
  
  CONCLUSIONS
  All nine voltage-gated sodium channels could be expressed by odontoblasts, depending on intradental location and tooth maturity. Our data reveal much greater complexity and niche-specific specialization for odontoblasts than previously demonstrated, with implications for tooth sensitivity.
authors.affiliation: Department of Anesthesiology & Pain Medicine, University of Washington, Seattle, WA 98195, United States. byersm@uw.edu
authors.forename: Margaret R
authors.initials: MR
authors.lastname: Byers
authors.forename: Ruth E
authors.initials: RE
authors.lastname: Westenbroek
mesh_terms: D000367:Age Factors; D000375:Aging / Q000235:genetics; D000818:Animals; D003782:Dental Pulp / Q000166:cytology / Q000378:metabolism*; D003804:Dentin / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D007180:Incisor / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D007381:Intermediate Filament Proteins / Q000096:biosynthesis; D015640:Ion Channel Gating / Q000235:genetics; D008963:Molar / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000096:biosynthesis; D064231:Nestin; D009474:Neurons / Q000378:metabolism; D009804:Odontoblasts / Q000378:metabolism*; D010519:Periodontium / Q000378:metabolism; D010641:Phenotype; D020033:Protein Isoforms; D051381:Rats; D015222:Sodium Channels / Q000096:biosynthesis* / Q000235:genetics; D000074025:TRPA1 Cation Channel; D050052:TRPC Cation Channels / Q000096:biosynthesis / Q000235:genetics; D013779:Tetrodotoxin / Q000494:pharmacology; D019228:Tooth Crown / Q000166:cytology / Q000378:metabolism; D014078:Tooth Eruption / Q000235:genetics; D014092:Tooth Root / Q000166:cytology / Q000378:metabolism
chemical_list: D007381:Intermediate Filament Proteins; D009419:Nerve Tissue Proteins; C577486:Nes protein, rat; D064231:Nestin; D020033:Protein Isoforms; D015222:Sodium Channels; D000074025:TRPA1 Cation Channel; D050052:TRPC Cation Channels; C480976:Trpa1 protein, rat; D013779:Tetrodotoxin