The platelet reticular network.

Human platelets have been observed by scanning electron microscopy after spreading on glass substrates followed by brief incubation in 1 mM ZnCl2 and subsequent shearing with a jet of buffer. The surfaces of many cells in such preparations are noted to consist of a reticular meshwork similar in appearance to the membrane skeleton of erythrocytes. In some preparations the reticular network is partially or almost entirely disrupted revealing an internal trabecular cytoskeleton and in the central region of the spread cell, granules associated with the cytoskeletal matrix. These results confirm previous observations obtained in TEM and HVEM studies of platelets and in addition provide information concerning the relative disposition of the filament systems in such spread cells. Preliminary results from sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis of platelets and isolated platelet membranes suggest a basis for the effect of ZnCl2 on various platelet cytoskeletal and membrane components.