Abstract
Lesions were placed in the spinal cord and sensory-motor cortex of adult cats in an attempt to produce transneuronal cell degeneration in the dorsal column nuclei. Animals were sacrificed at 30,60 and 90 postoperative days. Serial sections of the cervical cord and medulla were stained with cresyl violet. Other stains utilized were periodic acid Schiff, methyl green pyronin and phosphotungstic acid-hematoxylin.
Mild cellular changes, consisting of hypochromatic staining with cresyl violet, were noted at 30 days. Both mild and severe changes (consisting of alterations in cellular shape, staining and nuclear-nucleolar size) were noted at 60 days. Mainly severe changes were observed at 90 days. Histochemical techniques revealed that severely affected cells had stainable DNA within shrunken nuclei, enlarged nucleoli and a homogeneous proteinaceous deposit within their cytoplasm and pro- cesses.
Ninety day spinal lesions involving dorsal column afferents produced dense transneuronal pathology in the caudal zone of the gracilis. The cell nest zones of the gracilis and cuneatus contained several severely affected cells within individual cell clusters. The rostral zones of both nuclei contained only scattered severely pathological cells. Ninety day unilateral cortical lesions produced dense transneuronal pathology in a limited portion of the caudal gracilis. Rostral zones of both nuclei contained bilaterally symmetrical columns of severely affected cells, located at the junction between gracilis and cuneatus, throughout the length of these zones. Results are discussed in relation to the zonal division of these nuclei and the known organization of each zone.
