A Voltage-Dependent Transient K^+ Current in Rat Dental Pulp Cells

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Author(s)

Abstract

We characterized a voltage-dependent transient K<sup>+</sup> current in dental pulp fibroblasts on dental pulp slice preparations by using a nystatin perforated-patch recording configuration. The mean resting membrane potential of dental pulp fibroblasts was −53 mV. Depolarizing voltage steps to +60 mV from a holding potential of −80 mV evoked transient outward currents that are activated rapidly and subsequently inactivated during pulses. The activation threshold of the transient outward current was −40 mV. The reversal potential of the current closely followed the K<sup>+</sup> equilibrium potential, indicating that the current was selective for K<sup>+</sup>. The steady-state inactivation of the peak outward K<sup>+</sup> currents described by a Boltzmann function with half-inactivation occurred at −47 mV. The K<sup>+</sup> current exhibited rapid activation, and the time to peak amplitude of the current was dependent on the membrane potentials. The inactivation process of the current was well fitted with a single exponential function, and the current exhibited slow inactivating kinetics (the time constants of decay ranged from 353 ms at −20 mV to 217 ms at +60 mV). The K<sup>+</sup> current was sensitive to intracellular Cs<sup>+</sup> and to extracellular 4-aminopyridine in a concentration-dependent manner, but it was not sensitive to tetraethylammonium, mast cell degranulating peptide, and dendrotoxin-I. The blood depressing substance-I failed to block the K<sup>+</sup> current. These results indicated that dental pulp fibroblasts expressed a slow-inactivating transient K<sup>+</sup> current.<br>

Journal

  • The Japanese Journal of Physiology

    The Japanese Journal of Physiology 51(3), 345-353, 2001-06

    THE PHYSIOLOGICAL SOCIETY OF JAPAN

References:  28

Cited by:  3

Codes

  • NII Article ID (NAID)
    10008293820
  • NII NACSIS-CAT ID (NCID)
    AA00691224
  • Text Lang
    ENG
  • Article Type
    Journal Article
  • ISSN
    0021521X
  • NDL Article ID
    5840298
  • NDL Source Classification
    ZS8(科学技術--医学--解剖学・生理学・生化学)
  • NDL Call No.
    Z53-D40
  • Data Source
    CJP  CJPref  NDL  J-STAGE 
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