Fig. 4. Effect of Hr10 and eptifibatide on platelet aggregation and secretion.

a–c Dose–response curves (mean +/− s.e., n = 3 experiments, each from a different donor) showing effects of the inhibitors on aggregation induced by collagen (Coll.) (2 μg/ml) a, ADP (20 μM) b, or TRAP (10 μM) c. Points for the integrated impedance from the three experiments were individually normalized prior to averaging and are displayed with least-squares fits to the mean values. The respective IC₅₀, s.e., and p values (F-test, two-tailed) are listed in d. e–f Histograms (mean + or +/− s.d., n = 3 independent experiments) showing the effect of Hr10 and eptifibatide (each at 1.5 μM) on ADP (20 μM)-induced ATP secretion (e, p = 0.41, Student’s t-test, two-tailed) and surface expression of CD63 and CD62P f on human platelets. No differences in expression of CD63 (p = 0.15) or CD62P (p = 0.72), both Student’s t-test, two-tailed, were found in platelets exposed to eptifibatide or Hr10. Buffer sample in f represents marker expression in the absence of ADP.