The histochemical localisation of aminopeptidases in the central nervous system and an analysis of factors contributing to the final staining pattern.

A method is described for the localisation of aminopeptidases in the central nervous system. The enzymatic cleavage of the peptide bond in the substituted naphthylamide substrates results in the liberation of free naphthylamine which in the presence of an azo salt can be precipitated as a blue dye at sites of enzyme activity. Analysis of different brain regions using this technique indicates that these enzymes may have a specific function at certain sites in the CNS. Since this is the first method to produce any localised staining in nervous tissue an analysis of factors contributing to the final staining pattern is also presented.