MODIFICATIONS OF HISTOCHEMICAL TECHNIQUES FOR THE DEMONSTRATION OF CYTOCHROME OXIDASE

Four reagents were employed in conjunction with p-aminodiphenylamine as new histochemical substrates for cytochrome oxidase. The most useful [See figures in PDF file] substrates were 8-amino-1,2,3,4-tetrahydroquinone (I) and 8-hydroxy-1,4-naphthoquinone (III). (I) forms blue dyes and is recommended for general use, as well as for tissues of low activity (human gingiva). With the latter, the reaction may be augmented by the addition of cytochrome c. The dye produced from (III) has a strong affinity (substantivity) for tissue elements and resists dehydration with solvents. The new-substrates were useful in visualizing cytochrome oxidase activity in the digestive tract including oral mucosa, central nervous system, muscle and bone.