THE REGIONAL DISTRIBUTION OF NEURONAL GLYCOGEN IN THE OPOSSUM BRAIN, WITH SPECIAL REFERENCE TO HYPOTHALAMIC SYSTEMS

Neurons that accumulate glycogen have been identified in the opossum b rain stem and diencephalon by a modified histochemical method using al coholic solutions and fuchsin proper (pararosanilin) rather than the S chiff reagent (leucosulphite derivative). Several of the glycogen-posi tive cell groups such as the mesencephalic trigeminal nucleus and the brainstem somatic and special visceral efferent nuclei have been previ ously detected in the developing brain of small, common laboratory mam mals. Scattered glycogen-containing neurons also appear in the dorsal thalamus and basal forebrain. A conspicuous, often Golgi-like accumula tion of glycogen has been found in neurons of the magnocellular and pa rvocellular hypothalamic systems. Together with available data on the metabolic rate of marsupials, our results suggest that the patterns of glycogen deposition may be common to several vertebrates and may be a constant although not exclusive property of cells with axonal endings outside the blood-brain barrier.