title: Functional expression of TRPM8 and TRPA1 channels in rat odontoblasts.
abstract: Odontoblasts produce dentin during development, throughout life, and in response to pathological conditions by sensing stimulation of exposed dentin. The functional properties and localization patterns of transient receptor potential (TRP) melastatin subfamily member 8 (TRPM8) and ankyrin subfamily member 1 (TRPA1) channels in odontoblasts remain to be clarified. We investigated the localization and the pharmacological, biophysical, and mechano-sensitive properties of TRPM8 and TRPA1 channels in rat odontoblasts. Menthol and icilin increased the intracellular free Ca(2+) concentration ([Ca(2+)]i). Icilin-, WS3-, or WS12-induced [Ca(2+)]i increases were inhibited by capsazepine or 5-benzyloxytriptamine. The increase in [Ca(2+)]i elicited by allyl isothiocyanate (AITC) was inhibited by HC030031. WS12 and AITC exerted a desensitizing effect on [Ca(2+)]i increase. Low-temperature stimuli elicited [Ca(2+)]i increases that are sensitive to both 5-benzyloxytriptamine and HC030031. Hypotonic stimulation-induced membrane stretch increased [Ca(2+)]i; HC030031 but not 5-benzyloxytriptamine inhibited the effect. The results suggest that TRPM8 channels in rat odontoblasts play a role in detecting low-temperature stimulation of the dentin surface and that TRPA1 channels are involved in sensing membrane stretching and low-temperature stimulation. The results also indicate that odontoblasts act as mechanical and thermal receptor cells, detecting the stimulation of exposed dentin to drive multiple cellular functions, such as sensory transduction.
authors.affiliation: Department of Physiology, Tokyo Dental College, Chiba, Japan.
authors.forename: Maki
authors.initials: M
authors.lastname: Tsumura
authors.affiliation: Department of Physiology, Tokyo Dental College, Chiba, Japan ; Clinical Research Center, National Center for Child Health and Development, Tokyo, Japan.
authors.forename: Ubaidus
authors.initials: U
authors.lastname: Sobhan
authors.affiliation: Department of Physiology, Tokyo Dental College, Chiba, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Sato
authors.affiliation: Department of Clinical Oral Health Science, Tokyo Dental College, Tokyo, Japan.
authors.forename: Miyuki
authors.initials: M
authors.lastname: Shimada
authors.affiliation: Department of Oral Medicine, Oral and Maxillofacial Surgery, Tokyo Dental College, Chiba, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Nishiyama
authors.affiliation: Department of Dental Anesthesiology, Tokyo Dental College, Chiba, Japan.
authors.forename: Aya
authors.initials: A
authors.lastname: Kawaguchi
authors.affiliation: Department of Dental Anesthesiology, Tokyo Dental College, Chiba, Japan.
authors.forename: Manabu
authors.initials: M
authors.lastname: Soya
authors.affiliation: Department of Anesthesiology and Pain Relief Center, University of Tokyo Hospital, Tokyo, Japan.
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Kuroda
authors.affiliation: Department of Physiology, Tokyo Dental College, Chiba, Japan.
authors.forename: Masakazu
authors.initials: M
authors.lastname: Tazaki
authors.affiliation: Department of Physiology, Tokyo Dental College, Chiba, Japan.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Shibukawa
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects; D003804:Dentin / Q000187:drug effects / Q000378:metabolism; D008297:Male; D008610:Menthol / Q000494:pharmacology; D009804:Odontoblasts / Q000187:drug effects / Q000378:metabolism*; D011744:Pyrimidinones / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D000074025:TRPA1 Cation Channel; D050052:TRPC Cation Channels / Q000235:genetics / Q000378:metabolism*; D050053:TRPM Cation Channels / Q000235:genetics / Q000378:metabolism*
chemical_list: D011744:Pyrimidinones; D000074025:TRPA1 Cation Channel; D050052:TRPC Cation Channels; D050053:TRPM Cation Channels; C480976:Trpa1 protein, rat; C498947:Trpm8 protein, rat; D008610:Menthol; C490483:icilin; D002118:Calcium