Platelet activation calcium

Mazer, B., Domenico, J., Sawami, H. and Gelfand, E.W. (1991) Platelet-activating factor induces an increase in intracellular calcium and expression of regulatory genes in human B lymphoblastoid cells. Journal of Immunology 146, 1914-1920. 

Gardner, C.R., Laskin, J.D., and Laskin, D.L., Platelet-activating factor-induced calcium mobilization and oxidative metabolism in hepatic macrophages and endothelial cells, J. Leukoc. Biol., 53, 190, 1993. 

Siegel RK. (1979). Ginseng abuse syndrome. Problems with the panacea. JAMA. 241(15) 1614-15. Simon MF, Chap H, Braquet P, Douste-Blazy L. (1987). Effect of BN 52021, a specific antagonist of platelet activating factor (PAF-acether), on calcium movements and phosphatidic acid production induced by PAF-acether in human platelets. Thromb Res. 45(4) 299-309. 

Platelets can be activated by a variety of agents including the physiologic agonists ADP, thromboxane A2, epinephrine, collagen, and thrombin. Platelet activation is generally associated with a change in platelet shape (except for epinephrine-induced platelet activation) from discs to spiny spheres with pseudopodia. Platelet pseudopod formation is dependent on actin polymerization in the activated platelets. The interaction of actin filaments with myosin, mediated by calcium (9), facilitates platelet contractile activity (e.g., clot retraction). 

Platelet activation occurs in large part via G protein-coupled agonist receptors and intracellular signaling events that involve activation of phospholipase C (PLC). PLC catalyzes the breakdown of plasma membrane inositol phospholipids, resulting in generation of 1,2-diacylglycerol (DAG) and 1,4,5-inositol triphosphate (IP3). DAG activates protein kinase C, and IP3 induces mobilization of calcium from intracellular stores (10). 

Rediske, J. J., Quintavalla, J. C., Hasten, W. O., Morrissey, M. M., and Seligman, B. (1992). Platelet activating factor stimulates intracellular calcium transients in human neutrophils Involvement of endogenous 5-lipoxygenase products. J. Leukoc. Biol. 51, 484-489. 

Inhibition of phosphodiesterase, causing elevation of intracellular platelet cyclicAMP and a consequent reduction in calcium inhibitions this platelet activation and granule releases... 

Brass LF, Shattil SJ. Chaises in surfooe bound and exchangeable calcium during platelet activation. J Biol Chem 1982 257 14000-14005. 

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