Scanning electron microscopic observations of the common carotid artery of the rat. III. Heparin effect on platelets.

After administration of high systemic doses of heparin verified by assay, common carotid arteries in the rat were divided and sutured. Scanning electron microscope observations of endothelial surfaces showed a decrease in platelet adhesion, as well as a reduction in the adherence of other circulatory blood elements when compared to controls. This is the first report indicating the in vivo effect of high dose systemic heparin on platelets.