Effects of ADP and ATP on Bovine Fibrinogen‐ and Ristocetin‐Induced Platelet Aggregation in Glanzmann's Thrombasthenia

Abstract
Summary.: With thrombasthenic platelets, aggregation induced by ristocetin (R) and bovine fibrinogen (BF) is reversible, provided ATP is not added to the system. ADP inhibits BF and R induced aggregation, and when added after the onset of aggregation causes rapid disaggregation. ATP prevents these inhibitory and disaggregation effects of ADP. A mechanism is suggested whereby co‐operative effects occur between receptors in the membranes of thrombasthenic platelets.