Cytochalasin D enhances vWf-induced platelet aggregation independent of actin filament severing or ADP.

(A) Washed platelets (3 × 10⁸/mL) were preincubated with vehicle alone (control) or 5 μmol/L jasplakinolide (+ Jasp), and/or 5 μmol/L CD (+CD) for 10 minutes, prior to aggregation with 1 μg/mL BvWf. All aggregations were performed in the presence of 2 mmol/L EDTA. The aggregation tracings are from 1 experiment representative of 4 independent experiments performed in triplicate. (B) Washed platelets were preincubated with vehicle alone (control), 0.5 μg/mL PGE₁ (+ PGE₁) or PGE₁ and 5 μmol/L CD (+ PGE₁ + CD), then aggregated with BvWf (1 μg/mL). The tracings shown are from 1 experiment, representative of 5 independent experiments. (C) PRP was preincubated with either vehicle alone (control) or 5 μmol/L CD (+CD) for 10 minutes in the presence (+ apy) or absence of 0.5 U/mL apyrase. Aggregation of platelets was initiated with 1 mg/mL ristocetin. All aggregations were performed in the presence of anti-β₃ antibody, c7E3 Fab (20 μg/mL), to prevent vWf binding to integrin α_IIbβ₃. The aggregation tracings are from 1 experiment representative of 4 individual experiments performed in duplicate. (D) Washed platelets were preincubated with either vehicle alone (control) or 5 μmol/L CD for 0, 30, or 60 seconds, then aggregated with 1 μg/mL BvWf. All aggregations were performed in the presence of 2 mmol/L EDTA to block ligand binding to integrin α_IIbβ₃. The aggregation tracings are from 1 experiment representative of 5 individual experiments performed in duplicate.