Electron Microscope Studies of the Stria Vascularis and Spiral Ligament after Ferritin Injection

Abstract

Electron microscope studies of the transport and diffusion of macromolecules across the lateral wall of the cochlear duct were made after endolymphatic or perilymphatic injection of ferritin. After endolymphatic injection, the cells of the attachment zone of Reissner' membrane, the marginal cells of the stria vascularis, and cells of the spiral prominence and external sulcus absorbed the tracer but do not transport it across their cytoplasm. No ferritin was ever found in the spiral ligament. After ferritin injection into the perilymph the tracer was found in the spiral ligament and in the endothelial cells and lumen of the spiral ligament capillaries. Also it was found in cells of the attachment zone of Reissner' membrane, spiral prominence and external sulcus. In the stria vascularis ferritin was found only in the apical cytoplasm of the marginal cells. This was explained by transport from perilymph to endolymph across Reissner' metibrane. The functional significance of these findings were discussed.