Neurohistochemistry

Abstract

The critical interdependence of structure and function in neuronal units and assemblies has made neurological applications of the principles and techniques of histochemistry of particular significance. Broadly defined, these comprise all procedures that enable establishment of correlations between biochemical composition and histological and cytological structure. This array includes classical prodedures for in situ localization of chemical constituents and sites of enzymatic activities, the use of differential gradient and centrifugation methods for isolation of cellular and sub-cellular particles combined with biochemical analyses upon them, and the techniques of quantitative histochemistry in which tissue samples of microgram or sub-microgram sizes are directly analyzed by microchemical procedures. — Historically, the histochemistry of nervous tissues has been studied for a half-century. However, an explosive development has occurred during the last two decades, and a voluminous literature now exists upon neurohistochemical observations of many kinds. Clearly, it is impossible to review this subject in one afternoon. It is, however, pertinent to consider certain current activities of particular interest and importance. Relevant advances in methodology deserve consideration such as the reduction of in situ histochemistry to the level of the electron microscope, the use of fluorescence for cytologic localization of neurochemically important compounds, and the refinements of microchemistry enabling quantitative determinations upon single cells and even parts thereof. Extensive applications of all forms of histochemistry to regional neurocytology and neuropathology also merit discussion. — Accordingly, the program of this Symposion has been structured so as to present topics in (1) technical developments in histochemistry of special importance to neurobiology, (2) recent insights concerning biochemical fine structure in the central nervous system, in peripheral nerve, and in neuro-muscular end organs, and (3) applications of histochemistry to selected problems in neuropathology.