platelet aggregation is aided by
Platelet aggregation is aided by fibrinogen that binds to GPIIb/IIIa and forms a bridge between adjacent platelets. On activation, platelets also release their granules (platelet release reaction). The 5-HT that is released acts as a potent vasoconstrictor.ormation of platelets involves âpinching offâ bits of cytoplasm from the megakaryocyte, with each megakaryocyte giving rise to about 1000 platelets. The normal platelet count in blood is about 300 Ã 10 9 /litre. The structure of platelets is complex.