Ultrastructural localization of dpnh-diaphorase in the cochlea

Submicroscopic localization of DPm-diaphorase (NADH-cytochrome C reductase) in the glutaralde-hyde prefixed inner ear of the laboratory animals was studied utilizing TNBT (tetranitro blue tetrazo-lium) as an indicator. The strongest reaction was found in the mitochondria of the outer hair cells. The enzyme reaction was also found on the endoplasmic reticulum of the outer and inner hair cells, epithelial cells of the stria vascularis, Reissner's membrane, and connective tissue cells of the spiral ligament and limbus. Afferent nerve endings demonstrated diffuse enzyme reaction in their cytoplasm, however, efferent nerve endings showed dense reaction along the double membrane located opposite the nerve ending inside of the hair cells. Some of the interdental cells showed reaction in their cytoplasmic contents and showed differences of intensity of reaction among the interdental cells, possibly indicating different stages of enzyme activity.