Intraplatelet localization of the membrane-permeable peptides. Platelets incubated with FITC-conjugated peptides (250 μM) for 30 minutes and analyzed by flow cytometry and fluorescence microscopy. (A) Fluorescence histograms of platelets treated with FITC-conjugated myristoylated RGT peptide (FITC-myr-RGT, closed histogram) or with FITC-conjugated RGT peptide (FITC-RGT, open histogram) were analyzed by flow cytometry. (B) Platelets were treated with FITC-myr-RGT peptide or FITC-RGT peptide and allowed to spread on immobilized fibrinogen for 60 minutes. The same microscopic fields were analyzed by differential interference contrast (DIC) microscopy as well as confocal fluorescence microscopy (fluorescence). Figure shows representative images made by a Zeiss LSM510 confocal microscope with a 63× plan-apochromat DIC oil-immersion objective with Pascal software. (C) Z-Stack scanning was performed on FITC-myr-RGT-treated platelets with intervals of 1.2 μm (from 1 to 4). The fluorescence density profiles are shown below each picture.