Platelet-Bound and Soluble Platelet Factor 4: Effects of Aggregating Agents,of Aggregation,and of Aspirin 1

Abstract

Summary

If ADP is added to unstirred PRP, no aggregation occurs and platelet-bound heparin neutralizing activity (HNA) develops immediately; aspirin prevents the development of this HNA. ADP added to stirred PRP causes aggregation and no platelet-bound HNA is found. It is confirmed that if the release reaction occurs then a soluble form of HNA develops; pretreatment of the PRP with aspirin inhibits both the release reaction and the release of HNA. Adding epinephrine to PRP is not followed by demonstrable platelet-bound HNA, but soluble HNA is found if aggregation and release occur. The development of platelet-bound HNA presumably indicates a profound change in the platelet membrane.