Abstract
An enzyme for fluid transport, adenosine triphosphatase, has been studied in the stria vascularis and spiral ligament in the inner ear using various modifications of histochemical techniques for electron microscopy. We found enzyme activity appeared on the surfaces on the complex folds between the epithelial cells and on the surface facing the endolymph. Capillary basement membrane and mitochondria also showed marked activity. These findings are what one would expect of the stria vascularis considering its probable role in fluid transport and the findings of ATP-ase localization elsewhere.