Single-cell layer membrane covering the degenerated cochlear duct after perilymphatic perfusion of streptomycin.

Ultrastructural changes of the extrasensory epithelium in the scala media of guinea pig cochleae were observed from 3 to 137 days after perilymphatic perfusion with 20% streptomycin. The degeneration started in the organ of Corti, progressed to the interdental cells and roots of the outer sulcus cells and finally involved other epithelial cells such as Claudius and the inner and outer sulcus cells. In the final stage, except for the stria vascularis and Reissner's membrane, all epithelial cells which lined the cochlear duct were replaced by a single-cell layer membrane which originated medianly from the epithelial cells of Reissner's membrane and laterally from the superficial outer sulcus cells.