Ion channel involvement in the temperature-sensitive response of the rabbit corneal endothelial cell resting membrane potential

Mitchell A. Watsky, James L. Rae

Research output: Contribution to journalArticle

5 Scopus citations

Abstract

Previous studies have shown that the resting potential (Em) of the corneal endothelium hyperpolarizes following an increase in temperature above 24°C. Whole-cell studies using the perforated-patch technique were used to compare currents and Emvalues from isolated corneal endothelial cells at 24 and 32°C. These studies revealed a small, outwardly rectifying, slowly activating, weakly voltage-dependent current with a reversal potential showing K+ selectivity (Erev = -80 mV). This current had features similar to the whole-cell current seen following addition of HCO3- to these cells. Emmeasurements found an average 24 mV hyperpolarization following temperature elevation in NaCl Ringer. Single channel studies found the only change in channel activity following an elevation in temperature to be an increase in the open probability (Po) of a K+ channel previously reported in this cell type to be activated by external anions. Po(-30 mV) at 24 and 32°C equaled 0.003 and 0.06, respectively. Increases in Powere found at all voltages examined. This increased Pocan account for the magnitude of the hyperpolarization seen in these cells following temperature elevation. Addition of HCO3- along with elevated temperature produced a synergistic effect on the increase in Poalong with an increased hyperpolarization of the cell, pointing to separate mechanisms of activation from these two stimuli.

Original languageEnglish (US)
Pages (from-to)61-71
Number of pages11
JournalThe Journal of Membrane Biology
Volume135
Issue number1
DOIs
Publication statusPublished - Jul 1 1993
Externally publishedYes

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Keywords

  • Corneal endothelium
  • K channel
  • Patch clamp
  • Perforated patch
  • Resting voltage
  • Temperature sensitivity

ASJC Scopus subject areas

  • Biophysics
  • Physiology
  • Cell Biology

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