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Intracellular pH and Catecholamine Secretion from Bovine Adrenal Chromaffin Cells
Author(s) -
Kao LungSen,
Ho MeiYing,
Cragoe Edward J.
Publication year - 1991
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1991.tb06365.x
Subject(s) - catecholamine , intracellular ph , chromaffin cell , chemistry , exocytosis , secretion , amiloride , adrenal medulla , intracellular , carbachol , biophysics , biochemistry , sodium , endocrinology , biology , receptor , organic chemistry
: To study the role of intracellular pH (pH 1 ) in catecholamine secretion and the regulation of pH i in bovine chromaffin cells, the pH‐sensitive fluorescent indicator [2′,7′‐bis(carboxyethyl)‐5(6)‐carboxyfluorescein] was used to monitor the on‐line changes in pH i . The pH i of chromaffin cells at resting state is ⋍7.2. The pH 1 was manipulated first by incubation of the cells with NH 4 + , and then the solution was replaced with a NH 4 + ‐frce solution to induce acidification of the cytoplasm. The pH 1 returned toward the basal pH value after acidification within 5–10 min in the presence of Na + or Li + , but the pH 1 stayed acidic when Na + ‐free buffers were used or in the presence of amiloride and its analogues. These results suggest that the pH recovery process after an acid load is due to the Na + /H + exchange activity in the plasma membrane of the chromaffin cells. The Catecholamine secretion evoked by carbachol and Na + removal was enhanced after the cytoplasm had been made more acidic. It appears that acidic pH favors the occurrence of exocytosis.