Ultrastructural identification of neural elements containing trace metals.

The quantitative distribution of heavy metals in the central nervous system was studied by atomic absorption spectrophotometry. It was shown that, of the regions studied, the archicerebellar cortex contains the highest levels of metals. A light microscopical histochemical technique (TIMM silver sulphide method) reveals the neurons and glial cells which possess the trace elements. Ultrastructurally, the staining occurs in different axon terminals, lysosomes, neuronal surface membranes and the cytoplasm of glial cells.