Reversal of the inhibitory effect of Akt3 knockout on platelet aggregation by GSK-3β inhibitor SB216763. (A) Washed WT and Akt3^−/− platelets were pre-incubated for 2 minutes with 10μM of SB216763 or vehicle DMSO. These platelets were then stimulated with thrombin in a platelet aggregometer. (B) Washed WT mouse platelets were pre-incubated for 2 minutes with 10μM of SB216763 or vehicle DMSO and stimulated with a subthreshold concentration of thrombin in a platelet aggregometer. Platelet secretion was recorded concomitantly with aggregation in the presence of luciferase agent, and ATP release was recorded. (C) Washed mouse platelets were pre-incubated for 2 minutes with 10 μM of SB216763 or vehicle DMSO and then stimulated with collagen. Platelet ATP secretion was measured concomitantly. (D) Washed WT mouse platelets or Akt3^−/− platelets were pre-incubated with 10μM of SB216763 or vehicle DMSO and then stimulated with ADP (5μM) in the presence of fibrinogen (10 μg/mL) and platelet aggregation was recorded.