title: Measurement of ionized cytoplasmic calcium mobilization with the photoprotein aequorin in human polymorphonuclear leukocytes activated by platelet activating factor (PAF).
abstract: 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.
authors.affiliation: Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Del Maschio
authors.forename: M
authors.initials: M
authors.lastname: Albors
authors.forename: V
authors.initials: V
authors.lastname: Evangelista
authors.forename: F
authors.initials: F
authors.lastname: Bucchi
authors.forename: V
authors.initials: V
authors.lastname: Bertelé
authors.forename: C
authors.initials: C
authors.lastname: Cerletti
authors.forename: G
authors.initials: G
authors.lastname: de Gaetano
mesh_terms: D000331:Aequorin / Q000008:administration & dosage / Q000378:metabolism; D002118:Calcium / Q000097:blood*; D002449:Cell Aggregation / Q000187:drug effects; D003593:Cytoplasm / Q000378:metabolism; D005966:Glucuronidase / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D007975:Leukotriene B4 / Q000097:blood; D009113:Muramidase / Q000378:metabolism; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism; D010972:Platelet Activating Factor / Q000494:pharmacology*; D013481:Superoxides / Q000097:blood
chemical_list: D010972:Platelet Activating Factor; D013481:Superoxides; D007975:Leukotriene B4; D000331:Aequorin; D009113:Muramidase; D005966:Glucuronidase; D002118:Calcium