Effects of fibrinogen on ADP-evoked release of Ca++ from internal stores and P2x1receptor-mediated Ca++ entry.
(A) Fura-2–loaded human platelets were suspended in Ca++-free medium and stimulated with ADP (5 μM) in the absence (Control) or presence of fibrinogen (FG; 1 mg/mL). (B) Human platelets were suspended in an HBS containing 1 mM Ca++ in the presence of SKF96365 (50 μM). Platelets were then stimulated with ADP (5 μM) in the absence (SKF) or presence of fibrinogen (1 mg/mL) (FG + SKF). (C) Human platelets were suspended in an HBS containing 1 mM Ca++. Platelets were then stimulated with α,β-methylene ATP (10 μM) in the absence (Control) or presence of fibrinogen (FG; 1 mg/mL). Traces shown are representative of 6 to 10 independent experiments.
