STIMULUS-SECRETION COUPLING IN RAT PARIETAL-CELLS IS AFFECTED BY EXTRACELLULAR MAGNESIUM

We investigated the effects of extracellular magnesium on stimulus-sec retion coupling in isolated rat parietal cells. A high concentration o f extracellular magnesium (10mM) decreased basal and carbachol-stimula ted calcium levels, whereas low magnesium levels (0.2mM) had the oppos ite effect. The calcium-triggered acid secretion was influenced in the same manner. Basal and carbachol-stimulated acid secretion could be e nhanced by incubation in a buffer of low magnesium concentration, wher eas a high magnesium concentration totally suppressed the carbachol-in duced acid secretion. These results demonstrate that magnesium plays a modulative role in calcium-dependent stimulus-secretion coupling in r at parietal cells. (C) 1994 Academic Press, Inc.