[Protein cytochemistry in revealing the essentials of the structural and functional organization of the brain].

The histochemical method developed by the author was used to localize lysine- and arginine-rich proteins in the rat, rabbit, feline, canine, and human brains. A great difference was found between neurons (enlarged in lysine-rich proteins) and neuroglia (abundant in arginine-rich proteins). It was suggested that arginine-rich neuroglia might be responsible for or involved in supplying the brain with L-arginine, a precursor of nitric oxide (NO), a secondary messenger that is likely to be used by ancient type neurons. A direct relationship was established between the complexity of the brain structural and functional organization and the increases in lysine-rich neuronal proteins. This assumes that, by analogy with L-arginine synthesis of NO, L-lysine can be a precursor of a hypothetical messenger used by neurons of the higher brain regions. Responses of neurons to experimental exposures were assessed by the changes occurring in the levels of protein and its synthesis. Responses of neurons in the cortex and subcortical areas of the brain were shown to be non-specific and characterized by automatism, but to have specific features in different types of neurons.