Effect of Rho-kinase inhibition by Y-27632 and chelation of cytosolic Ca2+ by BAPTA plus EGTA on shape change (left) and cytosolic calcium levels (right). Platelets loaded with Fura2-AM were stimulated by various agonists. Shown are untreated control samples (C), samples preincubated with 20 μmol/L Y-27632 (Y), 20 μmol/L BAPTA-AM + 2 mmol/L EGTA (B+E), or both (B+E+Y). The arrow indicates addition of the agonist. Decrease of light transmission together with the disappearance of oscillations are indicative of shape change. (a) YFLLRNP (300 μmol/L). (b) Lower concentration of thrombin (0.01 U/mL). (c) Higher concentration of thrombin (0.05 U/mL). (d) U46619 (50 nmol/L). (e) ADP (2 μmol/L). (f) CRP (0.05 μg/mL). (g) Ionomycin (100 nmol/L). Results are representative of 4 to 6 independent experiments.
