SURFACE-MORPHOLOGY OF THE ENDOLYMPHATIC DUCT IN THE RAT - A SCANNING ELECTRON-MICROSCOPY STUDY

Following intracardiac vascular perfusion fixation of 8 rats with glut araldehyde in a buffered and oxygenated blood substitute, the vestibul ar aqueduct and endolymphatic duct were opened by microsurgery of the resulting 16 temporal bones. Optimum preservation of the epithelium fo r scanning electron microscopy was attained by coating of the specimen s with osmium tetroxide and thiocarbohydrazide followed by a continuou s dehydration procedure. This technique permitted, for the first time, an investigation of the surface morphology of the epithelial cells in the endolymphatic duct. Three types of cells were identified with the scanning electron microscope. A polygonal and oblong epithelial cell was observed in the largest number throughout the duct, and in the jux tasaccular half of the duct, two additional types of epithelial cells were observed. The scanning electron microscopic observations are comp ared and discussed with reference to previous transmission electron mi croscopic studies of the endolymphatic duct.