Platelet-activating factor (PAF) stimulates phosphatidylinositol hydrolysis in human peripheral blood mononuclear leukocytes.
Human peripheral blood mononuclear leukocytes were labeled with myo-[3H]inositol and stimulated by platelet-activating factor (PAF). PAF-induced phosphatidylinositol hydrolysis and inositol-1,4,5-trisphosphate (IP3) formation in a dose-dependent manner. The response was very rapid and transient and parallels the time course of PAF-induced calcium mobilization in the same cells. However, the doses of PAF for inducing IP3 formation were much higher than those for calcium mobilization. PAF-induced IP3 formation was inhibited by PAF receptor antagonist, L-659, 989, but was not altered by either pertussis toxin or cholera toxin. These data suggest that PAF receptor in human peripheral blood mononuclear leukocytes may be coupled through a pertussis toxin-insensitive guanine nucleotide binding protein to a phosphoinositide-specific phospholipase C.
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Department of Medicine, University of Alberta, Edmonton, Canada.
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D015220:Calcium Channels / Q000187:drug effects / Q000378:metabolism; D002772:Cholera Toxin / Q000494:pharmacology; D005663:Furans / Q000494:pharmacology; D006801:Humans; D006868:Hydrolysis; D066298:In Vitro Techniques; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism*; D037342:Pertussis Toxin; D010716:Phosphatidylinositols / Q000097:blood*; D010972:Platelet Activating Factor / Q000494:pharmacology*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D015220:Calcium Channels; D005663:Furans; D010716:Phosphatidylinositols; D010972:Platelet Activating Factor; D010566:Virulence Factors, Bordetella; C054893:L 659989; D002772:Cholera Toxin; D037342:Pertussis Toxin