Platelet aggregation and fibrinogen binding in human, rhesus monkey, guinea-pig, hamster and rat blood: activation by ADP and a thrombin receptor peptide and inhibition by glycoprotein IIb/IIIa antagonists.

摘要: Platelet aggregation and fibrinogen binding in whole blood, induced either by ADP or a 14 amino acid peptide mimicking an N-terminal region of the platelet thrombin receptor (TRP, activating peptide), have been studied with blood from different species. Aggregation was assessed counting number single platelets before und after addition agonist automated cell counter. Both (0.02-0.5 microM) TRP (1-10 were found to be potent agonists human, rhesus monkey guinea-pig causing near-maximal aggregatory response within 2 min addition. In contrast, hamster rat much less responsive both terms aggregation. Echistatin, RGDW synthetic glycoprotein (GP) IIb/IIIa antagonist, Ro 43-8857, inhibited purified immobilized human GP-IIb/IIIa IC50's 1.6, 88 11.4 nM, respectively. respective (as determined flow cytometric analysis binding) 4.4, 1700 29.5 nM. The affinities these three compounds for inhibiting monkeys guinea-pigs similar platelets, but echistatin, 43-8857 all around 100-fold potent. inhibitor ADP- TRP-induced (IC50 69-320 nM) active blood.(ABSTRACT TRUNCATED AT 250 WORDS)