Inhibition of actin polymerization enhances vWf-induced platelet aggregation.

(A) Washed platelets (3 × 10⁸/mL) were treated with the indicated concentration of CD prior to the performance of aggregation studies using BvWf (1 μg/mL). The aggregation tracings are from 1 experiment, representative of 5. (B) Washed platelets were treated with the indicated concentrations of CD prior to platelet stimulation with thrombin (1 U/mL) for 10 minutes. Cells were then lysed and F-actin content in the whole-cell lysates determined by actin filament sedimentation assays as described under “Materials and methods.” Results are the mean ± SE from 4 independent experiments. (C) Washed platelets were incubated with either vehicle alone (−LB) or 200 ng/mL latrunculin B (+LB), prior to the initiation of platelet aggregation with HvWf (0.5 μg/mL) in the presence of ristocetin (1 mg/mL). The aggregation tracings are from 1 experiment, representative of 3 performed in duplicate.