Objective In order to compare the functions of ADP in platelet aggregation and platelet membrane surface glycoproteins expression after thrombin receptors activation, then to investigate the role of ADP in thrombin signal transmission.

Methods Peptide SFLLRN (PAR1-AP, TRAP) and AYPGKF(PAR4-AP)were used for stimulating platelet at different time points (0~30minute) in 12 normal subjects, then the alterations of platelet aggregation and GPIbα, P-selectin were analyzed in the involvement of ADP inhibitor, ApyraseVII, which was observed by aggregometer and flowcytometry respectively.

Results Either PAR1 or PAR4 peptide can lead to platelet activation, inducing absolute platelet aggregation, together with a persistent increase of P-selectin and reversible interlisation of GPIb. Platelet aggregation was partly inhibited by ApyraseVII and showed a reversible curve upon PAR1 activation, and no change upon PAR4 activation. In addition, ApyraseVII accelerated the return of GPIb to platelet surface in PAR1 pathway, produced weak effect on GPIbα internalisation, … ltogether with little effect on GPIb alteration in PAR4 pathway. Meanwhile, no change of P-selectin was obtained in the involvement of Apyrase for both peptides.

Conclusion All the results confirm a critical role of ADP in thrombin signal transmission through the process of PAR1 pathway. ADP induces platelet aggregation and slows down the restoration of GPIb to platelet surface.

Topics:
thrombin receptor, receptor, par-1, peptides, p-selectin, thrombin, apyrase, cd40 ligand, membrane glycoproteins, telomeric repeat amplification protocol, thyroid hormone associated protein complex

Disclosure: No relevant conflicts of interest to declare.

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2006, The American Society of Hematology
2006
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