Figure 2.

Role for secondary signaling during Cl^–-dependent platelet aggregation. (a) Washed platelets were preincubated with 100 µM aspirin (cyclooxygenase inhibitor) and 5 U mL⁻¹ apyrase (ectonucleotidase) prior to performing aggregometry in the presence of 151 mM (black) or 1 mM (gray) [Cl⁻]_o. Representative traces (ai), maximum (aii), and initial rate (aiii) of thrombin-induced (0.1 U mL⁻¹) aggregation are shown in the presence of vehicle control (0.1% ethanol) or aspirin plus apyrase. (b) Summary data for maximum (bi) and initial rate of thrombin-evoked (0.1 U mL⁻¹) platelet aggregation (bii) in the presence of vehicle control (H₂O) or 1 µM Ar-C66096 (P2Y12 inhibitor). (c) Alpha (i) and dense (ii) granule release before (unstimulated) and after 0.1 U mL⁻¹ thrombin stimulation was assessed by flow cytometry using fluorescently labeled CD62P and CD63 antibodies, respectively. Data are representative of a minimum of four independent experiments and data were analyzed by two-way ANOVA.