[Platelet aggregation induced by adenosine diphosphate, collagen and adrenaline in human platelet subpopulations].

The study of platelet aggregation is normally carried out with the use of "Platelet Rich Plasma" (PRP) in which is grouped the overall platelets population. We have divided this population in three defined subclasses by gradients with discontinuous density, so as to test their own functional response towards three aggregant agents: adenosine diphosphate, epinephrine and collagen. The obtained results have been compared by an Aggregation Index, calculated as a ratio between the maximum percentage of aggregation and platelets mass. In this way it is pointed out a discriminating behaviour in three groups of thrombocytes relative to a functional different attitude towards different inducers and associated to an activation of heterogeneous way.