GW3965 inhibited fibrinogen binding to α_IIbβ₃ and granule secretion. (A-B) Human washed platelets (4 × 10⁸ cells/mL) were treated with GW3965 (1-10μM; Ai-ii,Bi-ii), T0901317 (10-40μM; Aiii,Biii), or vehicle, for 10 minutes stimulated with CRP (1 μg/mL) and analyzed by flow cytometry. Binding of antifibrinogen antibody to platelets and P-selectin exposure on platelet surface used as measures of α_IIbβ₃ activation (Ai) and α-granule secretion (Bi), respectively. (Aii-iii,Bii-iii) Data represent mean of median fluorescence values plus or minus SEM (n = 4). (C) ATP secretion traces from human platelets (4 × 10⁸ cells/mL) treated with GW3965 (10 or 20μM) for 10 minutes and stimulated by 1 μg/mL (Ci), 5 μg/mL (Cii), or 10 μg/mL of collagen (Ciii). ATP release was monitored using a luciferin-luciferase assay. (Civ) Collagen concentration response curve. Data are shown as amplitude of the secretion response in centimeters. Arrows above traces indicate the point of collagen addition. n ≥ 3. *P < .05. **P < .01.