Calcium channel current in rat dental pulp cells

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Abstract

Voltage-gated Ca2+ currents in early-passage rat dental pulp cells were studied using whole-cell patch-clamp techniques. With Ba2+ as the charge carrier, two prominent inwardly-directed currents, I(f) and I(s), were identified in these cells that could be distinguished on the basis of both kinetics and pharmacology. I(f) was activated by membrane depolarizations more positive than -30 mV, and displayed fast inactivation kinetics, while I(s) was activated by steeper depolarizations and inactivated more slowly. At peak current, time constants of inactivation for I(f) and I(s) were ~17 vs. ~631 msec. Both I(f) and I(s) could be blocked by lanthanum. By contrast, only I(s) was sensitive to either Bay-K or nifedipine, a specific agonist and antagonist, respectively, of L-type Ca2+ channels. I(s) was also blocked by the peptide omega-Conotoxin GVIA. Taken together, results suggested that I(f) was mediated by divalent cation flow through voltage-gated T-type Ca2+ channels, whereas I(s) was mediated by L- and N-type Ca2+ channels in the pulp cell membrane. The expression of these prominent, voltage-gated Ca2+ channels in a presumptive mineral-inductive phenotype suggests a functional significance vis a vis differentiation of dental pulp cells for the expression and secretion of matrix proteins, and/or formation of reparative dentin itself.

Original languageEnglish (US)
Pages (from-to)21-30
Number of pages10
JournalJournal of Membrane Biology
Volume178
Issue number1
DOIs
StatePublished - Nov 1 2000

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Keywords

  • Ca current
  • Conotoxin
  • Dental pulp
  • Dihydropyridine
  • In vitro
  • Lanthanum

ASJC Scopus subject areas

  • Biophysics
  • Physiology
  • Cell Biology

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