[Mechanism of the thrombin-platelet reaction]

In the course of investigations concerning the mechanism of the thrombin platelet interaction the conditions for the appearance of a refractory behaviour of platelets towards thrombin were examined. As investigation of the platelet reactivity by determining the amine liberation showed that a continuous or discontinuous addition of slight amounts of thrombin will cause the refractory condition. The findings were analyzed in view of the interaction between the dissolved enzyme and the fixed substrate. It is assumed that the number of receptors diminished after the first thrombin contact will cause a decrease of the receptor occupation speed on the platelet surface, thus leading to a decreased platelet reactivity.