[Effect of ASA on the interaction of von Willebrand factor with the platelet membrane].
Ristocetin induces a conformational change on von Willebrand Factor (vWF) similar to that due to the interaction with the subendothelium, by which the former can interact with the Glycoprotein-1 B (GPIB) of the platelet membrane and trigger aggregation and granule content secretion. Platelet Rich Plasma (PRP) treated with Acetyl Salicylic Acid (ASA) loses completely the aggregability induced by addition of Ristocetin whereas ASA-treated and successively Washed Platelets (AWP) supplemented with normal plasma (PPP) give an aggregation and a secretory response to Ristocetin similar to that given by PRP; similarly normal Washed Platelets (WP) supplemented with ASA-treated plasma (APPP) give identical aggregation, and secretion by Ristocetin addition. Ours results indicate that the Ristocetin-vWF complex can trigger two distinct intraplatelet metabolic pathways. A first well known way starts from the activation of Phospholipase A-2 (PL-A2), by which arachidonic acid is produced, that, in turn, undergoes the metabolic pathway leading to Thromboxane A-2; this pathway can be blocked by the intraplatelet ASA by irreversible inactivation of Cyclooxygenase, but it is insensitive to the extra-platelet ASA. A second, independent metabolic pathway, can be triggered by intact vWF, but not by the ASA treated one. It is insensitive to intraplatelet ASA and therefore unrelated to the arachidonic acid metabolism. This pathway could start from the activation of Phospholipase C (PL-C).
Ferri
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Istituto di Chimica Biologica, Università di Ferrara.
Anello
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G
Calza
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Bozza
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D001241:Aspirin / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D010974:Platelet Aggregation / Q000187:drug effects*; D010980:Platelet Membrane Glycoproteins / Q000187:drug effects*; D011485:Protein Binding / Q000187:drug effects; D014841:von Willebrand Factor / Q000187:drug effects*
D010980:Platelet Membrane Glycoproteins; D014841:von Willebrand Factor; D001241:Aspirin
Effetto di ASA sull'interazione del fattore di von Willebrand con la membrana piastrinica.