Time course of actin polymerization and spatial reorganization in stimulated platelets.
(A) After stimulation with 0.5 UI/mL THR (⋄), 10 μM TRAP (■), 250 pmol/L CVX (○), 2 μg/mL monoclonal IV.3 antibody followed by clustering of FcγRIIA with 30 μg/mL antimouse IgG F(ab′)2 for an additional 1 minute (▵) or control immunoglobulin (×), platelets were fixed in 1.8% paraformaldehyde, labeled with 10 μM FITC-phalloidin in 0.02% Triton X-100 buffer, and analyzed by flow cytometry. Results are expressed as ratios of mean fluorescence intensity (RFI) of stimulated to resting platelets and reported as means (± SD) of RFI from at least 6 experiments. (B) Platelets stimulated for 1 minute were also analyzed by confocal fluorescence microscopy (× 100). Results are representative of 3 separate experiments.
