Histochemistry of neuronal degenerative changes

Classical forms of degenerative changes of neurocytes, defined by Nissl and Spielmeyer as neuronal diseases were produced experimentally in rats. The individual neuronal changes were induced with the aid of X-ray irradiation, TET administration, ligation of the carotid artery followed by oxygen deficient breathing (anoxia), and by sectioning of the sciatic nerve. The so produced experimental models of neuronal diseases were the subject of morphological and cytochemical studies with special attention payed to enzymic and autoradiographic reactivity. Basing on the results of performed investigations, the author inferred that from a pathogenetic point of view, not all of the respective forms of neuronal diseases postulated by the classification of Nissl and Spielmeyer can be regarded as separate, distinct forms of degenerative changes. From the results obtained it would appear that pathogenetically distinct are only the following diseases: acute nerve cell swelling, shrinkage of perikaryons, homogenizing changes of Purkinje cells and axonal degeneration. The so called severe disease as well as the ischemic disease should be regarded as transitory forms of neuronal changes developing from shrunken neurocytes. It has also been suggested that the pathogenesis of homogenizing changes in Purkinje cells is distinct from that responsible for the development of ischemic changes in the course of cerebral anoxia and ischemia. This suggestion is substantiated by the observed differences in cytoenzymic reactivity between homogenized Purkinje cells and ischemically changed neurocytes.