Vesiculation and blebbing of fibrinogen-adherent platelets is impaired in the absence of CypD. Fibrinogen-adherent CypD^+/+ or CypD^−/− platelets were stimulated with thrombin (0.5 U/mL) (A,B) or thrombin (0.1 U/mL) plus convulxin (Cvx) (50 ng/mL) (C-F) for 2 minutes, fixed, and evaluated by scanning electron microscopy. Scale of the low-magnification images is indicated in panel D. Panels E and F show higher-magnification images of a vesiculated CypD^+/+ (E) and spread CypD^−/− (F) platelet. Images are representative of 4 separate experiments. Total magnification for panels A, B, C, and D is 2500×; total magnification for panels E and F is 7000×. Complete microscopy information is provided in “Electron microscopy.”