title: Inositol 1,4,5-trisphosphate receptor expression in odontoblast cells.
abstract: The cellular distribution of inositol 1,4,5-trisphosphate receptors was examined in rodent maxillary incisor teeth. In situ hybridization studies with a transmembrane probe of type I inositol 1,4,5-trisphosphate receptor indicated that this receptor/channel was highly expressed in odontoblast cells of incisor teeth. In contrast, very low labeling was observed in dental pulp. Northern analysis showed a message size of approximately 9.5 kilobases for this receptor, and demonstrated that type III inositol 1,4,5-trisphosphate receptor was expressed in incisor teeth. Immunocytochemical studies confirmed that types I and III inositol 1,4,5-trisphosphate receptors were both highly expressed in odontoblasts while very low expression was detected in dental pulp. Finally, antibodies that recognized alpha subunits of the Gq class of GTP binding proteins also stained odontoblasts. These results indicate that receptor-mediated regulation of calcium release through inositol 1,4,5-trisphosphate receptors may occur in odontoblasts of rat incisor teeth. These findings also suggest that inositol 1,4,5-trisphosphate receptor/channels regulate calcium flux in odontoblasts during mineralization of dentin, or in growth and differentiation of incisor tissue.
authors.affiliation: Department of Psychiatry, University of Pennsylvania School of Medicine, Philadelphia 19104, USA. smutzerg@mail.med.upenn.edu
authors.forename: G
authors.initials: G
authors.lastname: Smutzer
authors.forename: J E
authors.initials: JE
authors.lastname: Zimmerman
authors.forename: L Y
authors.initials: LY
authors.lastname: Han
authors.forename: D D
authors.initials: DD
authors.lastname: Ruscheinsky
authors.forename: S E
authors.initials: SE
authors.lastname: Arnold
authors.forename: X
authors.initials: X
authors.lastname: Yu
authors.forename: I
authors.initials: I
authors.lastname: Kratskin
mesh_terms: D000818:Animals; D015152:Blotting, Northern; D015220:Calcium Channels / Q000096:biosynthesis*; D002531:Cerebellum / Q000378:metabolism; D003782:Dental Pulp / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000096:biosynthesis; D006801:Humans; D017403:In Situ Hybridization; D007180:Incisor / Q000166:cytology / Q000378:metabolism; D053496:Inositol 1,4,5-Trisphosphate Receptors; D008437:Maxilla; D009804:Odontoblasts / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018160:Receptors, Cytoplasmic and Nuclear / Q000096:biosynthesis*
chemical_list: D015220:Calcium Channels; C506926:ITPR1 protein, human; D053496:Inositol 1,4,5-Trisphosphate Receptors; D018160:Receptors, Cytoplasmic and Nuclear; D019204:GTP-Binding Proteins