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Intracellular pH Changes During Neutrophil Activation: Na + /H + Antiport
Author(s) -
Weisman Steven J.,
Punzo Amalia,
Ford Charles,
Sha'afi Ramadan I.
Publication year - 1987
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1002/jlb.41.1.25
Subject(s) - antiporter , amiloride , protein kinase c , intracellular ph , intracellular , sodium–hydrogen antiporter , biochemistry , respiratory burst , biology , superoxide , phorbol , protein kinase a , chemistry , kinase , sodium , enzyme , organic chemistry , membrane
Activation of the Na + /H + antiport mechanism was studied in human neutrophils by monitoring intracellular pH with a carboxyfluorescein derivative. N‐formyl‐methionylleucyl‐phenylalanine (FMLP) and phospholipase C (PLC) induced biphasic pH changes. Amiloride, which inhibits the antiport, completely blocked alkalinization but enhanced acidification. Polymyxin B, which inhibits protein kinase C, only blocked alkalinization. Activation with phorbol 12‐myristate 13‐acetate (PMA) led to alkalinization only; this was inhibited by amiloride or polymyxin B. Thus, during polymorphonuclear leukocyte (PMN) activation, Intracellular alkalinization appears to be mediated by an amiloride‐sensitive Na + /H + antiport. Antiport activity can also be blocked indirectly by inhibition of protein kinase C activity. Early intracellular acidification does not appear to require kinase activity but is observed when phospholipids are remodeled with PLC. The antiport was also activatable by hypertonic buffered media. This response did not appear to be mediated by protein kinase C because it was unaffected by polymyxin B. Finally, superoxide generation was investigated. It is affected by, but not soley controlled by, either antiport or protein kinase C activity.