Acetylcholinesterase in the platelet-megakaryocyte system. I. Structural localization in platelets of the rat, mouse, and cat.

The localization of acetylcholinesterase (AchE) (E. C. 3.7.1.7) and peroxidase was studied cytochemically in blood platelets from cat, rat, mouse, and man. In a fraction (less than 1%) of cat, rat, and mouse platelets AchE activity was demonstrated in the dense, tubular membrane system (DTS), but activity was not detectable in human platelets. Some platelets showed AchE activity in granules distinct from alpha-granules. A fraction of the human platelet population exhibited a peroxidase-like activity in the DTS, but peroxidase activity was not detectable in cat, rat, and mouse platelets. The observations are interpreted to suggest a functional heterogeneity of the platelet population.