title: Influence of diamide on aggregation, cytoskeletal proteins, and arachidonic acid metabolism in human platelets.
abstract: Simultaneous addition of diamide (azodicarboxylic acid-bis-dimethylamide, DIA), a SH-oxidizing agent, and collagen causes a deaggregation of otherwise irreversibly aggregating platelets. Thromboxane B2 (TXB2) and 12-HE-TE formation is inhibited depending on the concentration ratio between collagen and DIA. Thus, at 0.25 mM DIA and 20 micrograms/ml collagen neither TXB2 nor 12-HETE were measurable, but a full scale reversible aggregation is induced. Deaggregation is further attained by adding DIA to collagen-induced aggregates at a time, when maximum amplitude has been achieved. Investigation of arachidonic acid (AA) metabolites under these conditions revealed no influence of DIA on AA metabolism. Therefore, AA metabolization seems to play a minor role in collagen-induced aggregation and DIA-induced deaggregation. Polymerization of certain cytoskeletal proteins of the platelets, after addition of DIA, parallels DIA-induced deaggregation. DIA inhibits endogenous AA release, probably by interaction with platelet plasma membrane. DIA seems to inhibit the release of the alpha-granula protein thrombospondin.
mesh_terms: D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000097:blood*; D001391:Azo Compounds / Q000494:pharmacology*; D001667:Binding, Competitive; D001792:Blood Platelets / Q000378:metabolism*; D003094:Collagen / Q000494:pharmacology; D003598:Cytoskeletal Proteins / Q000097:blood*; D003958:Diamide / Q000494:pharmacology*; D006801:Humans; D006893:Hydroxyeicosatetraenoic Acids / Q000097:blood; D066298:In Vitro Techniques; D010974:Platelet Aggregation / Q000187:drug effects*; D013929:Thromboxane B2 / Q000097:blood
chemical_list: D001095:Arachidonic Acids; D001391:Azo Compounds; D003598:Cytoskeletal Proteins; D006893:Hydroxyeicosatetraenoic Acids; D003958:Diamide; D016718:Arachidonic Acid; D013929:Thromboxane B2; D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; D003094:Collagen