Two types of K+ currents in marginal cells cultured from rat stria vascularis

Sang Jeong Kim, Steven S Juhn

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

Membrane currents in marginal cells cultured from rat stria vascularis were studied using the whole-cell patch-clamp technique. Two types of voltage-dependent whole-cell currents were observed in the voltage range from -150 mV to +50 mV: an outwardly rectifying current and an inwardly rectifying current. The outwardly rectifying current, which was activated by depolarizing pulses more positive than -30 mV, was sensitive to TEA (20 mM) and relatively not to Ba2+ (0.5 mM). Tail current analysis revealed that the outward currents were primarily K+-selective. The conductance of the current was half-maximal at 0.5 mV and a substantial portion of current was not inactivated by the depolarizing prepulses from -30 mV to +20 mV. The inwardly rectifying current with rapid exponential activation was observed with hyperpolarizing voltage pulses. The zero-current potential of this current was dependent on extracellular K+ concentration. In contrast to the outwardly rectifying current, this current was blocked by extracellular application of Ba2+, not by TEA. The conductance of this current increased with the increase in external K+ concentration. Our data suggest that marginal cells cultured from rat stria vascularis express at least two types of voltage-dependent K+ currents which may serve as K+ secretory pathways into endolymph.

Original languageEnglish (US)
Pages (from-to)186-198
Number of pages13
JournalHearing Research
Volume112
Issue number1-2
DOIs
StatePublished - Oct 1 1997

Keywords

  • Inward rectifier
  • K current
  • Marginal cell
  • Outward rectifier
  • Stria vascularis

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