ISSN:
1432-1424
Keywords:
Key words: Dental pulp — Ca2+ current — Dihydropyridine — Lanthanum — Conotoxin — In vitro
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
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.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s002320010011
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