Effects of DCB or bepridil on [Ca²⁺]_i changes by thrombin. Washed platelets (1 × 10⁵/μL) loaded with fluo-3-AM were suspended in modified Tyrode Hepes buffer containing 1 mmol/L CaCl₂ in the absence or presence of indicated dose of inhibitors. Probenecid (2 mmol/L) was added to prevent leakage of the dye from platelets. The fluo-3-loaded platelets were stimulated with 0.1 U/mL thrombin, and the cytosolic-free calcium concentration ([Ca²⁺]_i) was determined on a Hitachi F-3000 spectrofluorometer using wavelength of 485 and 530 nm for excitation and emission, respectively. The suspension was gently stirred (100 rpm) during the measurement. These results are representative of three separate experiments.