Effects of DCB, bepridil, or Ro31-8220 on protein phosphorylation evoked by thrombin. Washed platelets (3 × 10⁵ /μL) labeled with ³²P were stimulated with (A, lanes 5 to 8) or without (A, lanes 1 to 4) 0.1 U/mL thrombin in the absence (A, lanes 1, 5; B, ○) or the presence of 10 μmol/L DCB (A, lanes 2, 6; B, •), 80 μmol/L bepridil (A: lanes 3, 7; B, □) or 4 μmol/L Ro31-8220 (A, lanes 4, 8; B, ▪) for indicated duration. The platelets were lysed and proteins were separated by 7.5% SDS-PAGE. (A) Autoradiography is shown (arrow head, pleckstrin; arrow, MLC). (B) Relative quantification of the extent of phosphorylation of 47-kD and 20-kD proteins was performed using Bioimage analyzer and normalized to a 100 % value for phosphorylation before thrombin-stimulation. Results are the mean ± SD from three separate experiments.