Properties of whole-cell ionic currents in cultured human corneal epithelial cells

Invest Ophthalmol Vis Sci. 1998 Jun;39(7):1143-51.

Abstract

Purpose: To identify and partially characterize the ionic currents contributing to the whole-cell conductance of cultured human corneal epithelial cells.

Methods: Epithelial cells were scraped from human donor corneas and cultured for use in patch-clamp experiments. Amphotericin B and the perforated-patch configuration were used to measure whole-cell currents in cells isolated from confluent monolayers.

Results: Cell monolayers exhibited cobblestone morphology and were immunopositive for corneal epithelium-specific cytokeratin. Single cells had a capacitance of 21 +/- 2 pF and expressed similar types of ionic currents regardless of passage number. In descending order of frequency of occurrence, cells exhibited a nonselective cation current active at depolarized voltages and insensitive to Ba2+ and Gd3+; an outwardly rectifying K+ current active at depolarized voltages, stimulated by flufenamic acid and inhibited by tetraethylammonium; a voltage-gated inward Na+ current; an outwardly rectifying K+ current active at hyperpolarized voltages, stimulated by flufenamic acid, blocked by Ba2+, and insensitive to diltiazem; an inwardly rectifying K+ current; and a nonselective cation current inhibited by flufenamic acid.

Conclusions: Our results are consistent with those in previous studies of noncultured epithelia from rabbit and human corneas showing an outwardly rectifying K+ current active at hyperpolarized voltages and a nonselective cation current active at depolarized voltages and insensitive to Ba2+. These data suggest cultured cells may be useful in determining the physiological role of ion channels in corneal epithelia and may aid in the development of a cell-based model for the examination of the effects of wounding and toxic agents on the human cornea.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amphotericin B / pharmacology
  • Cells, Cultured
  • Epithelium, Corneal / cytology
  • Epithelium, Corneal / drug effects
  • Epithelium, Corneal / physiology*
  • Female
  • Flufenamic Acid / pharmacology
  • Humans
  • Infant
  • Infant, Newborn
  • Ion Channels / physiology*
  • Ion Transport
  • Patch-Clamp Techniques
  • Potassium / metabolism
  • Potassium Channels / physiology
  • Sodium / metabolism

Substances

  • Ion Channels
  • Potassium Channels
  • Flufenamic Acid
  • Amphotericin B
  • Sodium
  • Potassium