Platelet aggregation induced by NNKY5-5 as assessed by aggregometry using light scatter. Platelet aggregation was measured using PRP anticoagulated with citrate (A and B) or 50 U/mL hirudin (C). (A) NNKY5-5 (10 μg/mL) was added to PRP (arrow) and the changes in light transmission (LT, solid line) and light scatter (LS, broken line) were monitored simultaneously. (B) GRGDS (400 μmol/L) was added 10 minutes before the addition of 10 μg/mL NNKY5-5 (arrow). (C) Hirudin was used to maintain a physiological concentration of Ca²⁺ and NNKY5-5 (10 μg/mL) was added at the time indicated by the arrow. Light scatter intensity of 0.2 to 2V, which represents platelet aggregates of small size, is shown in arbitary units. The data are representative of at least four experiments.