The abilities of human blood platelets to bind extracellular calcium and to be aggregated by adenosine diphosphate are related.
A technique is described for preparing platelets rich plasma containing a very low level of extracellular calcium. Using this Ca-depleted PRP it has been possible to demonstrate that extraplatelet calcium is in equilibrium with a small amount of calcium that is bound to the platelet surface. When Ca-depleted PRP is incubated at 37 degrees C the platelets lose their ability to bind calcium. At the same time they lose their ability to aggregate. It is likely that the binding of calcium to the platelet surface is a prerequisite for ADP-induced aggregation.
D000244:Adenosine Diphosphate / Q000494:pharmacology; D001792:Blood Platelets / Q000378:metabolism*; D002118:Calcium / Q000097:blood*; D006801:Humans; D066298:In Vitro Techniques; D010974:Platelet Aggregation / Q000187:drug effects; D013696:Temperature
D000244:Adenosine Diphosphate; D002118:Calcium