Platelet Aggregation and the Ouabain-lnsensitive ATPase

Wang, Teh Yu, Hussey, Clara V., Sasse, Edward A., and Hause, Lawrence L.: Platelet aggregation and the ouabain-insensitive ATP-ase. Ecto-ATPase, reflection of membrane integrity. Am J Clin Pathol 67: 528-532, 1977. The ecto-ATPase activity of washed human platelets has been characterized by a higher-performance liquid chromatographic method. Mg was found to stimulate ecto-ATPase activity more strongly than Ca. The combination of Mg and Ca at increasing concentrations caused diminishing activity levels. Elevated ecto-ATPase activity was also found in platelets incubated with prostaglandin E, (PGE,) or potassium cyanide (KCN). It is proposed that the increase of ecto-ATPase activity is related to the extrusion or exposure of plasma membrane containing a ouabain-insensitive ATPase. The role of ecto-ATPase in platelet aggregation is discussed in light of these findings. (