Characterization of platelet‐activating factor‐induced elevation of cytosolic free calcium concentration in eosinophils

FEBS Letters

Yukawa, Tatsuo¹  Westwick, John²  Pleass, Robert²  Barnes, Peter J.¹  Kroegel, Claus¹  Chung, K.Fan¹ 

[1] Department of Thoracic Medicine, National Heart and Lung Institute, Brompton Hospital, University of London, Dovehouse Street, London SW6 LY6, England;Department of Pharmacology, The Hunterian Institute, Royal College of Surgeons, Lincoln's Inn Fields, London WC2A 3PN, England

关键词: Ca2+ concentration;    intracellular;    Platelet-activating factor;    Platelet-activating factor antagonist WEB 2086;   

DOI  :  10.1016/0014-5793(89)81214-1

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

In order to evaluate the role of calcium in the activation processes in eosinophils induced by platelet-activating factor (PAF), we investigated the changes in free cytoplasmatic Ca²⁺ concentration using fura-2. PAF causes a rapid and transitory rise of the intracellular free calcium ion concentration ([Ca²⁺]_i) in purified guinea pig eosinophils of approx. 1000 nM above a basal level of 120.7 ± 36.5 nM (n = 10). The effect was dose-related with a maximum rise at 1000 nM PAF and an EC₅₀ of 17.4 nM and specifically inhibited by the PAF antagonist WEB 2086 with an IC₅₀, of 95.5 nM. WEB 2086 did not affect either the leukotriene B₄- or the fMet-Leu-Phe-induced elevation of [C²⁺]_i. The response to PAF was dependent on external Ca²⁺ as it was significantly inhibited by EGTA (85.6 ± 5.4%) and Ni²⁺ (95.8 ± 2.1 %) but not by the dihydropyridine antagonist nimodipine. We conclude that Ca²⁺ entry via receptor-operated Ca²⁺ channels may be involved in PAF-induced degranulation of eosinophils.

【 授权许可】

Unknown