Is cytosolic ionized calcium regulating neutrophil activation?

Science. 1983 Sep 30;221(4618):1413-5. doi: 10.1126/science.6310757.


The concentration of cytosolic ionized calcium, [Ca2+]i, was measured in intact neutrophils by use of a fluorescent indicator trapped in the icytoplasm. A given rise of [Ca2+]i elicited by the chemotactic peptide formylmethionylleucylphenylalanine (FMLP) was associated with a much greater degree of superoxide generation and myeloperoxidase secretion than was the same or larger [Ca2+]i produced by a specific calcium ionophore, ionomycin, which bypasses cell surface receptors. Thus, FMLP appears to generate some important excitatory signal in addition to a rise in [Ca2+]i and exocytosis and superoxide generation in neutrophils may not be simply dependent on [Ca2+]i as is widely supposed.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Calcium / physiology*
  • Cytoplasm / physiology
  • Ethers / pharmacology
  • Exocytosis*
  • Humans
  • Ionomycin
  • Ionophores / pharmacology
  • Lysosomes / enzymology
  • N-Formylmethionine / analogs & derivatives
  • N-Formylmethionine / pharmacology
  • N-Formylmethionine Leucyl-Phenylalanine
  • Neutrophils / physiology*
  • Oligopeptides / pharmacology
  • Oxygen / metabolism*
  • Superoxides / metabolism*


  • Ethers
  • Ionophores
  • Oligopeptides
  • Superoxides
  • N-Formylmethionine
  • Ionomycin
  • N-Formylmethionine Leucyl-Phenylalanine
  • Oxygen
  • Calcium