A microprobe analysis of Gomori-positive glial cells in the rat arcuate nucleus.

Astrocytes and microglial cells in the arcuate nucleus of the rat hypothalamus contain lipofuscin-like granules which react with chrome alum gallocyanin and exhibit endogenous peroxidase activity. These granules were assessed with energy dispersive X-ray microanalysis and compared to neuronal dense bodies and glial cytoplasm. The granules are distinguished by a consistent content of sulphur and a frequent presence of calcium. The localization of other elements such as iron, copper, potassium and chlorine is impaired by methodical difficulties. The sulphur content as well as the endogenous peroxidase activity is interpreted as indicating a special variant of lipofuscin. The presence of calcium is discussed with respect to recent concepts of glia as a regulator of the ionic environment of the CNS.