Effects of monovalent cations and anions on ADP-induced aggregation of bovine platelets, and mechanisms thereof.
The effects of monovalent cations-inorganic alkali metal cations and organic quaternary ammonium cations-and monovalent inorganic anions on ADP-induced aggregation of bovine platelets were investigated. In the presence of K+, Rb+, Cs+, choline or tetramethylammonium, aggregation proceeded. However, aggregation was markedly restricted in media containing Li+, Na+, tetrabutylammonium or dimethyldibenzylammonium. With anions, aggregation proceeded in the order Cl- greater than Br- greater than I- greater than ClO4- greater than SCN-. The effects of cations significantly depended on Ca2+ concentration, whereas those of the anions depended little on Ca2+. Anions such as SCN- and ClO4- markedly decreased the fluorescence of the surface charge probe 2-p-toluidinyl-naphthalene-6-sulfonate, whereas cations had less pronounced effects. The relative effects of the anions on the fluorescence were consistent with their relative inhibitory effects on aggregation. These results suggest that inhibition of platelet aggregation by the anions is due to a change in the surface change of the platelet plasma membrane. On the other hand, kinetic analysis suggests that the effects of monovalent cations on platelet aggregation are due to their competition with Ca2+ during the process of aggregation.
D000244:Adenosine Diphosphate / Q000494:pharmacology*; D000818:Animals; D000838:Anions; D001667:Binding, Competitive; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism; D002118:Calcium / Q000494:pharmacology; D002414:Cations, Monovalent; D002417:Cattle; D066298:In Vitro Techniques; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects; D010974:Platelet Aggregation / Q000187:drug effects*
D000838:Anions; D002414:Cations, Monovalent; D000244:Adenosine Diphosphate; D002118:Calcium