Potassium and chloride currents in rat gastric enterochromaffin-like cells.
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.
Loo
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DD
Department of Physiology, University of California at Los Angeles School of Medicine 90095-1751, USA.
Sachs
G
G
Prinz
C
C
D000818:Animals; D002478:Cells, Cultured; D002712:Chlorides / Q000502:physiology*; D002838:Chromaffin System / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D004553:Electric Conductivity; D005260:Female; D005755:Gastrins / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D011188:Potassium / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012844:Sincalide / Q000494:pharmacology; D013270:Stomach / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D002712:Chlorides; D005755:Gastrins; D012844:Sincalide; D013755:Tetradecanoylphorbol Acetate; D011188:Potassium