Endothelial-ADPase degrades the platelet activator ADP. In all mammals, coagulation involves both a cellular (platelet) and a protein (coagulation factor) component. The result is inhibition of platelet aggregation. They work by preventing platelet aggregation and thrombus formation. It works by reducing platelet aggregation and thrombus formation. Platelet activation begins seconds after adhesion occurs. It may function as a blood platelet activation marker. ITP is an autoimmune disease with antibodies detectable against several platelet surface structures. Symptoms of ITP include abnormal bleeding and bruising due to the reduction in platelet count. Antiplatelets are drugs that interfere with platelet aggregation. It also serves as a signalling molecule to induce platelet aggregation. Thrombin also promotes secondary fibrin-reinforcement of the platelet plug. Platelet transfusions are generally not recommended. Conversely, thromboxanes (produced by platelet cells) are vasoconstrictors and facilitate platelet aggregation. Uraemia can lead to alteration of platelet aggregation.