Block Intensification and X-Ray Microanalysis of Cobalt-Filled Neurons for Electron Microscopy
Many special methods visualize a nerve cell in its entirety. Modifications of Golgi’s (1873) silver impregnation (Strausfeld 1980) stochastically select single nerve cells. The more selective modern neuronal markers include labelling with various metals (Kerkut and Walker 1962; Lux and Globus 1968), injection of dyes and fluorescent markers (Thomas and Wilson 1966; Kato et al. 1968; Stretton and Kravitz 1968, 1973; Kater and Nicholson 1973; Stewart 1978), application of enzyme proteins (see Chap. 3) and specific antibody staining (see Chaps. 12–16). All these methods give invaluable information concerning function, shape and chemical identity of neurons within a neuropil. However, the identification of small structures that imply functional connections, such as synapses, can only be done at high resolution by electron microscopy. This requires good tissue preservation, a feature that is lacking in all labelling methods developed for light microscopy alone. Furthermore, a marker substance is required that allows identification of the neuron at low magnification by light microscopy and produces sufficient electron scattering at the fine-structural level for its own unambiguous detection.
KeywordsSucrose Sulphide DMSO Epoxy Uranium
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