Potassium and Chloride Currents in Rat Gastric Enterochromaffin-Like Cells

Am J Physiol. 1996 May;270(5):E739-45. doi: 10.1152/ajpgi.1996.270.5.G739.

Abstract

The gastric enterochromaffin-like (ECL) cell secretes histamine in response to secretagogues (gastrin, acetylcholine) by calcium signaling-dependent exocytosis of intracellular vacuoles containing the hormone. ECL cells were isolated from rat fundic gastric mucosa by elutriation and density-gradient centrifugation. Currents across the plasma membrane were measured using whole cell patchclamp methods. These cells had a low conductance of 0.5 nS and resting potential of -50 mV. Depolarization activated a K+ current that was blocked by Ba2+. Steady-state current in absence of K+ was due to Cl- because of the magnitude of the reversal potential and the effects of Cl- removal. Stimulation of secretion by gastrin, cholecystokinin octapeptide (CCK-8), and the phorbol ester 12-O-tetradecanoylphorbol 13-acetate activated the Cl- conductance with a time course similar to that of histamine release. Therefore the ECL cell maintains a high resting potential, largely due to K+ currents, and stimulation of secretion activates a Cl- current, perhaps deriving from the membrane of the secretory granule that fuses with the plasma membrane. The depolarization that ensues may activate the K+ current to maintain the membrane potential during exocytosis.

Publication types

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

MeSH terms

  • Animals
  • Cells, Cultured
  • Chlorides / physiology*
  • Chromaffin System / cytology
  • Chromaffin System / drug effects
  • Chromaffin System / physiology*
  • Electric Conductivity
  • Female
  • Gastrins / pharmacology
  • Patch-Clamp Techniques
  • Potassium / physiology*
  • Rats
  • Rats, Sprague-Dawley
  • Sincalide / pharmacology
  • Stomach / cytology
  • Stomach / drug effects
  • Stomach / physiology*
  • Tetradecanoylphorbol Acetate / pharmacology

Substances

  • Chlorides
  • Gastrins
  • Sincalide
  • Tetradecanoylphorbol Acetate
  • Potassium