Membrane microrheological properties of platelets at rest and after thrombin-induced aggregation: A spin-label study

Abstract

Using the spin-label method, we have compared the physical state of the human platelet membrane before and after thrombin-induced aggregation. In its resting state this membrane is rigid and highly organized. After aggregation, its ordering decreases. This phenomenon is dose dependent and reaches its maximum with about 0.5 U/ml of thrombin for 3.10⁹ platelets per ml. Preliminary results obtained on genetic diseases (Glanzman thrombasthenia and Gray platelets syndrome) indicate that this change is independent from the aggregation phenomenon itself. In thromboembolic states (thrombocytemia, diabetes) the membrane molecular structure of platelets at rest seems to be similar to that of activated normal platelets.