Figure 1
Effect of fibrinogen on Aβ25–35-induced platelet activation. (A) Tracings 1, 2, 3 and 4 represent platelet aggregation in PRP induced by Aβ25–35 (20 and 50 µmol/L), ADP (20 µmol/L) and collagen (10 µg/mL), respectively. The corresponding bar diagram is shown in the lower panel. (B) Tracings 1–4 represent aggregation, and tracings 1′-4′ represent corresponding dense granule secretion in washed platelets stimulated with either thrombin (1 U/mL; tracings 2 and 2′) or Aβ25_35 (20 µmol/L; tracings 1, 1′, 3, 3′, 4 and 4′). Tracings 3 and 3′ represent platelets pretreated with fibrinogen (2 mg/mL), whereas tracings 4 and 4′ represent platelets pretreated with BSA (2 mg/mL). Corresponding bar diagram is shown in the lower panel. (C) Tracings 1, 2, 3 and 4 represent aggregation of washed platelets induced by Aβ25_35 (20 µmol/L) in the presence of 3, 2, 1.5 and 0.75 mg/mL fibrinogen, respectively. Corresponding bar diagram is shown in the lower panel. (D) Tracings 1, 2, 3 and 4 represent aggregation of washed platelets induced by Aβ25–35 (20,30,40 and 60 µmol/L, respectively) in the presence of fibrinogen (2 mg/mL). Corresponding bar diagram is shown in the lower panel. (E) Flow cytometric analysis of expression of P-selectin on surface of platelets treated with different reagents and agonists as indicated. (F) Retraction of fibrin clot by platelets stimulated with either Aβ25–35 (20 µmol/L) or ADP (20 µmol/L) in presence of fibrinogen (2 mg/mL) added either before or after exposure to agonists as indicated.