Characterization of platelet-activating factor-induced cytosolic calcium mobilization in human eosinophils
Article first published online: 23 SEP 2008
Clinical & Experimental Allergy
Volume 30, Issue 5, pages 699–705, May 2000
How to Cite
Oshiro, Kakuta, Shimura, Nara and Shirato (2000), Characterization of platelet-activating factor-induced cytosolic calcium mobilization in human eosinophils. Clinical & Experimental Allergy, 30: 699–705. doi: 10.1046/j.1365-2222.2000.00786.x
- Issue published online: 23 SEP 2008
- Article first published online: 23 SEP 2008
- Ca2+-capacitative entry ;
- cytosolic-free calcium;
- human eosinophils;
- platelet-activating factor;
- protein kinase C;
Activated eosinophils play an important role in the pathogenesis of bronchial asthma and other allergic diseases, and platelet-activating factor (PAF) is a potent activator of eosinophils.
To characterize the cytosolic Ca2+ ([Ca2+]i) mobilization in human eosinophils in response to PAF.
[Ca2+]i responses to PAF were examined in human eosinophils using a microscopic fura-2 fluorescence-ratio imaging system.
PAF caused a significant and dose-dependent increase in (Ca2+)i, which consisted of an initial rapid rise followed by a sustained elevation. This PAF-induced (Ca2+)i rise was inhibited by WEB 2086, a specific PAF receptor antagonist. The addition of 5 m m EGTA or 1 m m Ni2+ to a nominally Ca2+-free solution did not appreciably reduce the initial rise but significantly inhibited the sustained rise. The application of a protein kinase C inhibitor, Ro31-8220, augmented the sustained increase by PAF. Thapsigargin, a microsomal Ca2+ ATPase inhibitor, induced no appreciable change in a nominally Ca2+-free solution but induced a marked increase in (Ca2+)i when changed to a Ca2+-containing solution.
The initial rapid rise and the following sustained rise in (Ca2+)i by PAF depends on Ca2+ release from the intracellular Ca2+ stores and Ca2+ influx, respectively, which are regulated by protein kinase C in human eosinophils. Furthermore, the so called Ca2+-capacitative entry is possibly involved in the Ca2+ influx from the extracellular solution in human eosinophils.