[The morphology of the glial cells in the inferior olivary complex of ground squirrels (Citellus citellus L.). I. Oligodendrocytes].

The morphological characteristics of oligodendrocytes in the lower olivary complex of ground squirrels at various ages were studied by light and electron microscopes. On the basis of an analysis on thick sections, stained with toluidine blue, it was established that nuclei of these cells were smaller and darker in comparison with those of astrocytes. The mean oligodendrocytes, located in perineuronal, perifascicular, perineuronal-perifascicular, interfascicular, perivascular position or freely situated, predominated in the neuropile of the lower olivary complex. Changes in their ultrastructure were investigated during advancement of age and during the process of aging. An increase in the number of heterogeneous dense bodies were found as well as the presence of lipid-pigmented granules with crystal-like brightening. The connection of oligodendrocyte growth with myelin sheath of axons.