Changes of platelet membrane associated Ca2+ during storage and by 37C incubation with fresh plasma

The relationship between platelet aggregability and membrane associated Ca2+ measured by the use of chlortetracycline was studied. When platelet concentrates were stored at room temperature for 3 days, the relative value of platelet membrane-Ca2+ amount increased. But when stored platelets were incubated at 37C with fresh plasma, platelet membrane-Ca2+ decreased, and at the same time, ADP-induced aggregability increased. The relative value of membrane-Ca2+ amount and ADP-induced aggregability exhibited reverse correlation. According to these results, it is supposed that one of the factors which cause the decreased platelet aggregability during storage and partial recovery by 37C incubation with fresh plasma, is the change of the distribution of platelet Ca2+.