Ionic channels in corneal endothelium

James L. Rae, Mitchell A. Watsky

Research output: Contribution to journalReview article

28 Scopus citations

Abstract

Single-channel patch-clamp techniques as well as standard and perforated- patch whole cell voltage-clamp techniques have been applied to the study of ionic channels in the corneal endothelium of several species. These studies have revealed two major K+ currents. One is due to an anion- and temperature-stimulated channel that is blocked by Ca+ but not by most other K+ channel blockers, and the other is similar to the family of A-currents found in excitable cells. The A-current is transient after a depolarizing voltage step and is blocked by both 4-aminopyridine and quinidine. These two currents are probably responsible for setting the -50 to -60 mV resting voltage reported for these cells. A Ca2+activated ATP-inhibited nonselective cation channel and a tetrodotoxin-blocked Na+ channel are possible Na+ inflow pathways, but, given their gating properties, it is not certain that either channel works under physiological conditions. A large- conductance anion channel has also been identified by single-channel patch- clamp techniques. Single corneal endothelial cells have input resistances of 5-10 GΩ and have steady-state K+ currents that are ~10 pA at the resting voltage. Pairs or monolayers of cells are electrically coupled and dye coupled through gap junctions.

Original languageEnglish (US)
Pages (from-to)C975-C989
JournalAmerican Journal of Physiology - Cell Physiology
Volume270
Issue number4 39-4
Publication statusPublished - Apr 1 1996
Externally publishedYes

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Keywords

  • anion channel
  • cation channel
  • cornea
  • electrophysiology
  • patch clamp
  • potassium channel
  • transport
  • whole cell clamp

ASJC Scopus subject areas

  • Physiology
  • Cell Biology

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