Measurement of ionized cytoplasmic calcium mobilization with the photoprotein aequorin in human polymorphonuclear leukocytes activated by platelet activating factor (PAF)

A. Del Maschio, M. Albors, V. Evangelista, F. Bucchi, V. Bertele, C. Cerletti, G. De Gaetano

Research output: Contribution to journalArticle


The use of the sensitive photoprotein aequorin as a Ca2+ indicator in human polymorphonuclear leukocytes (PMN) not pretreated with cytochalasin B and stimulated with platelet activating factor (PAF) may help cast more light on the relative importance of intracellular and extracellular Ca2+ in PMN function. PAF elicits Ca2+ mobilization in PMN (resuspended in the presence of 1 mM extracellular Ca2+), in a concentration-dependent manner. The Ca2+ chelator ethyleneglycoltetraacetic acid (EGTA) abolishes Ca2+ mobilization, suggesting that almost all Ca2+ mobilized by PAF derives from the external medium. Aggregation and enzymatic release parallel the Ca2+ mobilization triggered by PAF. In contrast PAF appears to be only a weak stimulus of superoxide anion production (compared to the phorbol ester phorbol 12-myristate 13-acetate (PMA)) and leukotriene B4 (LTB4) synthesis (compared to the Ca2+ ionophore A23187). The fact that PAF elicits Ca2+ mobilization, aggregation, secretion and LTB4 generation in human PMN supports the role of this phospholipid as a powerful mediator of physiopathological events involving PMN activation.

Original languageEnglish
Pages (from-to)25-36
Number of pages12
JournalJournal of Lipid Mediators
Issue number1
Publication statusPublished - 1989


ASJC Scopus subject areas

  • Immunology
  • Pharmacology

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