title: Changes of platelet functions by extracellular sodium ion.
abstract: Effects of extracellular Na+ on platelet responses were examined. Cytoplasmic pH decreased by stimulation with thrombin, TPA and AA in Na(+)-containing buffer as well as in Na(+)-free buffer. Thrombin-induced aggregation and serotonin release were higher in Na(+)-containing buffer, but TPA- and A23187-induced responses exhibited lower values. Thrombin-stimulated platelet in Na(+)-free buffer started to aggregate by the addition of NaCl. Inhibition of thrombin-induced aggregation by indomethacin was apparently weaker than that by removal of Na+. These results suggest that the changes of platelet responses by removal of Na+ is due to the effect of Na+ ion itself, not by the inhibition of Na+/H+ exchanger, and that Na+ affects on mechanisms other than arachidonic acid mobilization.
authors.affiliation: Japanese Red Cross Central Blood Center, Tokyo.
authors.forename: Y
authors.initials: Y
authors.lastname: Ishikawa
authors.forename: A
authors.initials: A
authors.lastname: Ogawa
authors.forename: S
authors.initials: S
authors.lastname: Sasakawa
mesh_terms: D000584:Amiloride / Q000031:analogs & derivatives / Q000494:pharmacology; D001095:Arachidonic Acids / Q000494:pharmacology; D001792:Blood Platelets / Q000187:drug effects* / Q000502:physiology; D000001:Calcimycin / Q000494:pharmacology; D003593:Cytoplasm / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007213:Indomethacin / Q000494:pharmacology; D010974:Platelet Aggregation / Q000187:drug effects*; D012701:Serotonin / Q000032:analysis; D012964:Sodium / Q000494:pharmacology*; D013917:Thrombin / Q000494:pharmacology; D010959:Tissue Plasminogen Activator / Q000494:pharmacology
chemical_list: D001095:Arachidonic Acids; D012701:Serotonin; D000001:Calcimycin; D000584:Amiloride; D012964:Sodium; D013917:Thrombin; D010959:Tissue Plasminogen Activator; C039614:ethylisopropylamiloride; D007213:Indomethacin