Abstract
1. Pathohistological studies were conducted on the brain especially the cerebellum of rabbits in which sodium nitrite, the methemoglobin-forming toxin, was injected in doses of 40, 60, and 80 mg/kg once daily for a short and long period.
2. Basic and permanent changes consisted of changes due to disturbance of blood circulation, such as congestion and edematous porotic changes. Degenerative changes of paren-chymatous cells were also seen.
3. The histological localization of early and characteristic injuries to the parenchymatous cells is in the ganglion cells or Purkinje cells showing degenerative atrophy or swelling imbibition, finally falling out and disappearance.
4. Degeneration, atrophy and disappearance of small granular cells in the granular layer was seen, so that this layer as the whole gives a porotic appearance.
5. Later in the course of time, degenerative changes were also seen in the molecular and medullary layer.
6. When these changes became more pronounced, the borderline between each cortical layer and between the cortical and medullary layer became indistinct. Mild degeneration of the vascular wall and perivascular edema was also noted.
7. The effect on cerebellum in the present experiment consisted of hypoxia causing disturbance in blood circulation and early degenerative changes of the parenchymatous cells through respiratory inhibition. The changes of Purkinje cells were especially pronounced, probably representing an expression of the dynamic aspect of blood distribution in relation to cells and tissues based on hypoxia and generalized circulatory disturbance. Purkinje cells in the cerebellum thus appear to become an index of hypoxic change.
