title: Depolarization-induced Intracellular Free Calcium Concentration Increases Show No Desensitizing Effect in Rat Odontoblasts.
abstract: Odontoblasts play an important role in the transduction of the sensory signals underlying dentinal pain. Transmembrane voltage-independent Ca(2+) influx in odontoblasts has been well described. Voltage-dependent Ca(2+) influx has also been reported, but its biophysical properties remain unclear. The aim of the present study was to investigate the desensitizing effect of voltage-dependent Ca(2+) influx in rat odontoblasts by measuring depolarization-induced intracellular free Ca(2+) concentrations ([Ca(2+) ]i ). Odontoblasts on dental pulp slices from newborn rats were acutely isolated and [Ca(2+) ]i measured by using fura-2 fluorescence. Repeated application of extracellular high-K(+) solution (50 mM), which induces membrane depolarization-elicited repeated and transient increases in [Ca(2+) ]i in the presence of extracellular Ca(2+). Increases in depolarization-induced [Ca(2+) ]i showed no significant desensitizing effect (p >0.05; Friedman test). These results suggest that odontoblasts express a voltage-dependent Ca(2+) influx pathway with no desensitizing properties.
authors.affiliation: Department of Physiology, Tokyo Dental College.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Kojima
authors.forename: Asuka
authors.initials: A
authors.lastname: Higashikawa
authors.forename: Maki
authors.initials: M
authors.lastname: Kimura
authors.forename: Masaki
authors.initials: M
authors.lastname: Sato
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Mochizuki
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Ogura
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Sase
authors.forename: Akinori
authors.initials: A
authors.lastname: Shinya
authors.forename: Kunio
authors.initials: K
authors.lastname: Kobune
authors.forename: Tadashi
authors.initials: T
authors.lastname: Furuya
authors.forename: Toru
authors.initials: T
authors.lastname: Sato
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Shibukawa
authors.forename: Masakazu
authors.initials: M
authors.lastname: Tazaki
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling; D003593:Cytoplasm; D016257:Fura-2; D009804:Odontoblasts / Q000737:chemistry*; D051381:Rats
chemical_list: D002118:Calcium; D016257:Fura-2