Pretreatment of platelets with DEVD-fmk (100 μmol/L for 1 hour) does not alter agonist-induced platelet aggregation or  granule secretion. (A and B) Absence of effect of DEVD-fmk on platelet aggregation induced by (A) A23187 (1 μmol/L) or (B) thrombin (1 U/mL). (C) Absence of effect of DEVD-fmk on thrombin-induced  granule secretion. The histograms show surface expression of the  granule membrane marker CD62P, which is absent on resting platelets (left) and upregulated on treatment with thrombin for 30 seconds (middle) or 60 seconds (right). Note that DEVD-fmk pretreatment (dashed lines) did not alter thrombin-induced upregulation of CD62P.