Platelet secretion of washed platelets from control or SERCA3−/− mice. Dense granule secretion from platelets aggregated in the presence of collagen (A; 0.8 or 1.2 µg/mL) or thrombin (B; 40 or 100 mU/mL), with the addition (+) or not (-) of 10 µM ADP, was assessed by measuring ATP release in picomoles (calculated for 107 platelets) in control (WT, black bars) and SERCA3−/− (gray bars) platelets. A total of 3 experiments were conducted and presented as mean ± SEM, using 1-way ANOVA followed by Tukey’s multiple comparison test; ns, not significant; ***P < .001. (C) The expression of the α-granule membrane marker P-selectin following thrombin platelet stimulation was assessed by flow cytometry on control (black bars) or SERCA3−/− (gray bars) platelets. The same experiment was conducted in the presence of apyrase (5 U/mL, noted “+ Apy”) or added ADP (10 µM, noted “+ ADP”) on control (WT, black bars) or SERCA3−/− (gray bars) platelets. Data presented are the means of 3 separate experiments in duplicates, as means ± SEM, as assessed by 1-way ANOVA followed by Tukey’s multiple comparison test; ns, not significant; **P < .01.
