In vitro morphological study of cochlear epithelium.

1. The mammalian cochlear epithelium was successfully kept alive in long-term tissue cultures. The Na and K concentration of the culture medium was similar to that of perilymph. 2. The most vulnerable cells in the culture epithelium were the outer and inner hair cells followed by the inner zones cells and the interdental cells of the spiral limbus. The difference in disintegration time between the outer and inner hair cells was about 48 hrs under the same culture conditions. The same phenomenon was noted between the rows of outer hair cells. 3. When the outer hair cells were not supported by Deiters' cells or when the cochlear epithelium was separated between Deiters' cells and Hensens cells, the outer hair cells degenerated quickly. 4. The interdental cells appeared to be relatively highly differentiated and showed much activity. No evidence of secretory function of interdental cells could be obtained. 5. The inner sulcus cells, Hensens cells, Claudius' cells and Reissners membrane cells were flattened and arranged like covering epithelium.