Calcium‐activated membrane depolarization via modulation of chloride efflux from parietal cells during gastrin stimulation

[摘要]

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.

[学科分类] 生物化学/生物物理

[关键词] Gastrin;Ca2+ release;Depolarization;Cl− efflux;(Parietal cell;Guinea pig);fura-2;1-(2-(5′-carboxyoxazol-2′-yl)-6-aminobenzofuran -5-oxy)-2-(2′-amino-5′-methylphenoxy-ethane-N;N;N′;N′-tetraacetic acid;BAPTA;1;2-bis(o - aminophenoxy)ethane - N;N;N′;N′ - tetraacetic acid;diS-C3-(5);3;3′-dipropylthiodicarbocyanine;Mops;3-(N-morpholino)propanesulfonic acid;quin-2;2-(2-amino-5-methylphenoxy)methyl-6-methoxy-8-aminoquinoline-N;N;N′;N′-tetraacetic acid