HISTOCHEMICAL DEMONSTRATION OF CYTOCHROME OXIDASE WITH NEW AMINE REAGENTS

A series of aryl amines were employed as new histochemical reagents for the demonstration of cytochrome oxidase. The amines, upon oxidation, form indamine-azine type dyes which are capable of chelating with a number of metals. The most useful substrate consisted of a mixture of N-phenyl- p-phenylenediamine (I) and p-methoxy- p-aminodiphenylamine (II) or 3-amino-9-ethyl-carbazole (V). The reaction was inhibited by pretreatment of sections with saline, and augmented by the addition of cytochrome c. Heat, cyanide, and sulfide were inhibitory. Although raw-frozen sections were employed, mitochondrial localizations were obtained in specific instances in selected areas of certain tissues. The possibility of demonstrating other oxidative enzymes with these substrates warrants further study.