[Effect of heparin on the aggregation function of thrombocytes]

It has been demonstrated in experiments in vitro that addition of heparin to platelet enriched plasma potentiates the ADP-induced platelet aggregation and that heparin itself can provoke aggregation of platelets. Heparin exerts an inhibitory action on the thrombin-induced aggregation, which seems likely to be associated with its inhibitory effect on thrombin, an inducer of aggregation. It has been discovered that heparin action on the hemostasis is determined by its concentration. The doses under 0.05 U/ml enhance the ADP-induced platelet aggregation and accelerate the time of blood coagulation, whereas the doses from 0.3 to 2 U/ml exert a more powerful effect on aggregation, inhibiting blood coagulation.