Histochemical studies on the morphology of the Golgi apparatus and on the distribution of some enzymes concerned with carbohydrate metabolism in the rat cerebellum

Abstract

Detailed histochemical studies have been conducted on the distribution of various enzymes, including thiamine pyrophosphatase, alpha-glucan phosphorylase, hexokinase, glucose-6-phosphate dehydrogenase, aldolase, glycerol-3-phosphate dehydrogenase; menadion oxidoreductase, lactate dehydrogenase and succinate dehydrogenase in various components of the cerebellum of healthy adult male rats of the Wistar strain. The thiamine pyrophosphatase reaction showed the morphological patterns of the GOLGI apparatus characteristic for each kind of cells. The GOLGI apparatus is a simple network in stellate cells, but it can be classified into the same 5 categories in basket cells and GOLGI type II cells. The GOLGI apparatus in the latter 2 cell types appears to undergo cyclic changes. A few GOLGI type II cells have a supranuclear form (Type II) and some cells show disintegration and "budding-off" of the GOLGI apparatus. The GOLGI apparatus in PURKINJE cells can be classified into 4 categories including a perinuclear strand form (Type III), but most of them show randomly distributed granules and vesicles. Lightly stained networks are observable in astrocytes and oligodendrocytes. They do not show polarity in astrocytes whereas they have extensions in a few oligodendrocytes. BERGMANN glia may undergo cyclic changes indicating more advance differentiation than astrocytes and oligodendrocytes. Cerebellar glomerula show lightly stained networks with many fine granules. Granule cells, stellate cells, and basket cells are all poorly equipped equally with the EMBDEN-MEYERHOF (EM) pathway and with the hexosemonophosphate (HMP) shunt. GOLGI type II cells are richly equipped almost equally with both the EM pathway and the HMP shunt. All these neurons probably derive energy mainly from glucose in the circulating blood. PURKINJE cells may belong to the category of "usual neurons", because they are moderately equipped both with the EM pathway and the HMP shunt. However, they may derive their energy from the BERGMANN glia which have intense hexokinase activity but weak succinate dehydrogenase activity. The BERGMANN glia are more richly equipped with the HMP shunt than with the EM pathway and are rich in lactate dehydrogenase suggesting an "exceptional metabolic pattern". These glia may have active synthesizing ability. Astrocytes and oligodendrocytes are equipped with all the enzymes tested, and they show a tendency to surround the glomeruli. It is suggested that the glomerula may be surrounded by the glial sheaths with strong hexokinase activity, and that they may contain alpha-glucan phosphorylase, glucose-6-phosphate dehydrogenase, and glycerol-3-phosphate dehydrogenase in addition to the succinate dehydrogenase already reported. A few PURKINJE cells showed perinuclear concentrations of the reaction product only of succinate dehydrogenase at the sites of contacts between nucleoli and nuclear membranes. It is suggested that the nucleolus may receive adenosine at the sites of contacts between nucleoli and nuclear membranes...