[II. Ultrastructure of rat superior cervical ganglion cells in organ culture and grafts].

Ultrastructural modifications of neurons in organ cultures were more and less obvious, while remaining always identical in cultures at the same age. Between 5 and 6 days after culture, neurons showed numerous dense bodies, nuclear pockets, sparse Nissl's bodies broken into fragments, bundles of microfilaments, elongated mitochondria and a slightly distended Golgi apparatus. Sometimes, the nucleus was indented and the nucleolus was shaded off. S.I.F. cells had indented nucleus, dense bodies and bundles of microfibrils. Neurons from direct grafts presented modifications similar to those observed in cultures at short time intervals. Then the breaking up of Nissl's bodies and mitochondria and the hyalin transformation of dense bodies took place. A restoration, at first involving the nucleus, could occur in relation with immunological conditions. The evolution of S.I.F. cells was quite comparable to that of neurons. In either case, features of cellular degeneracy were always little marked and fugitive.