Calcium-activated membrane depolarization via modulation of chloride efflux from parietal cells during gastrin stimulation.
In the isolated parietal cell the following observations were made: gastrin led to an increase in cytoplasmic free Ca2+ concentration ([Ca2+]i) even in the absence of medium Ca2+ and to transient membrane depolarization in both the absence of the medium Ca2+ and the fura-2-loaded cell. The incorporated Ca2+ chelator BAPTA inhibited the gastrin-induced membrane depolarization. The magnitude of depolarization caused by gastrin was unchanged on removal of medium Na+. Furosemide but not tetraethylammonium inhibited the gastrin-induced depolarization. The results suggest that the Ca2+ released from the store(s) induces membrane depolarization, possibly via modulation of a Cl- efflux across the luminal surface during gastrin stimulation.
D000818:Animals; D001572:Benzofurans / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology / Q000502:physiology*; D002217:Carbachol / Q000494:pharmacology; D002614:Chelating Agents / Q000494:pharmacology; D002712:Chlorides / Q000378:metabolism*; D004987:Ethers / Q000494:pharmacology; D016257:Fura-2; D005665:Furosemide / Q000494:pharmacology; D005755:Gastrins / Q000494:pharmacology*; D006168:Guinea Pigs; D066298:In Vitro Techniques; D015759:Ionomycin; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects; D010295:Parietal Cells, Gastric / Q000187:drug effects / Q000502:physiology*; D019789:Tetraethylammonium; D013757:Tetraethylammonium Compounds / Q000494:pharmacology
D001572:Benzofurans; D002614:Chelating Agents; D002712:Chlorides; D004987:Ethers; D005755:Gastrins; D013757:Tetraethylammonium Compounds; D015759:Ionomycin; D019789:Tetraethylammonium; D005665:Furosemide; D002217:Carbachol; D002118:Calcium; D016257:Fura-2