Highly Efficient Induction of Human Platelet Aggregation in Heparinized Platelet-Rich Plasma by Diadenosine Triphosphate (Ap₃A)

Summary

Diadenosine triphosphate (Ap₃A), which is a releasable dinucleotide of human platelets, induces platelet aggregation when added to heparinized platelet-rich plasma. The concentration dependence of the dinucleotide is similar to ADP. This finding is fully compatible with our recent report of the low potency of Ap₃A in citrated platelet-rich plasma relative to ADP.

The aggregatory effect of Ap₃A in heparinized versus citrated plasma is reflected in the corresponding rates of Ap₃A degradation. In citrated plasma, the hydrolysis of Ap₃A is drastically slowed down because the hydrolase needs divalent metal ions. The results strongly support the assumption that the aggregatory effect of Ap₃A is mediated by the enzymatic hydrolysis of Ap₃A which generates ADP as the ultimate stimulus.

Keywords

Diadenosine triphosphate - Ap₃A - Platelet aggregation - ADP - Heparin - Citrate

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