[Electron microscopic study of the structural variability of activated Schwann cells]

The structural variability of Schwann cell is studied on transsectioned sciatic nerves of rats using the electron microscope. Corresponding to histological and cytological changes in the proximal nerve stump and in the growing sprouts processes of regression and progression take place in different phases of nerve regeneration. Under this conditions the Schwann-cells can show a considerably varying ultrastructural cytology. Besides typical Schwann cells modulations can be distinguished differing in their organelle composition, such as light-cells, macrophage-like cells and highly synthetic active and roliferative forms. The importance of these cell modulations is discussed in relation to the functional properties of Schwann cells.