Figure 3.

Myosin inhibitor, blebbistatin(-) and Rho kinase inhibitor, Y-27632 inhibited clot retraction. Human washed platelets (5 × 10⁸/ml) were preincubated with 80 μM blebbistatin(-), 80 μM blebbistatin(+) (A), DMSO, or 20 μM Y-27632 (B). Clot retraction assays were started by adding 250 μl of 2 U/ml thrombin to 250 μl of platelets in the presence of 2 mg/ml fibrinogen and 2 mM CaCl₂ (final concentrations: 2.5 × 10⁸/ml of platelets, 1 U/ml of thrombin, 1 mg/ml of fibrinogen, 1 mM CaCl₂). The volume of remaining fluid was measured to assay the degree of clot retraction. The volume was expressed as mean ± SE (n = 4–7 from 2 experiments). Results were analyzed using unpaired Student's t-test. One asterisk denotes p < 0.05 and two denote p < 0.005 between the controls and the inhibitors.