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Platelet activating factor stimulates intracellular calcium transients in human neutrophils: involvement of endogenous 5‐lipoxygenase products
Author(s) -
Rediske John J.,
Quintavalla Joe C.,
Haston William O.,
Morrissey Michael M.,
Seligman Bruce
Publication year - 1992
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.51.5.484
Subject(s) - leukotriene b4 , platelet activating factor , calcium , arachidonate 5 lipoxygenase , stimulation , calcium in biology , biology , lipoxygenase , endogeny , leukotriene , platelet , endocrinology , medicine , inflammation , immunology , biochemistry , enzyme , arachidonic acid , asthma
Stimulation of human neutrophils with platelet activating factor (PAF) resulted in a transient elevation of free cytosolic calcium. Neutrophils exhibited a two‐component calcium response observed as a double peak when stimulated with > 5 nM PAF. In contrast, leukotriene B 4 (LTB 4 ), C5a, or formylmethionyl‐leucyl‐phenylalanine stimulated only a single‐peak calcium response. The double‐peak calcium response was not elicited in human monocytes or differentiated U937 cells, which demonstrated a single peak. Pretreatment of neutrophils with a 5‐lipoxygenase inhibitor or a specific LTB 4 ‐receptor antagonist selectively blocked the second calcium peak. These results suggest that PAF‐mediated activation of human neutrophils results in the activation of the 5‐lipoxygenase and the subsequent generation of LTB 4 . This LTB 4 in turn elicits a secondary rise in calcium, which contributes to the overall response of neutrophils to PAF. These results demonstrate how LTB 4 participates in the cellular responses elicited by PAF in human neutrophils.