Electron microscopical studies on the nerve endings of the outer hair cells in acoustically exposed rabbits.

The afferent and efferent nerve endings of the outer hair cells of the rabbit after acoustic exposure were investigated under the electron microscope. After acoustic stimulation, the afferent and efferent nerve endings of normal range were respectively 57 per cent and 64 per cent. This result suggests that half of the afferent and efferent nerve endings maintain their function under the conditions of this experiment. An abnormal inclusion body forming an oblong dense body and cistern in addition to the postsynaptic cisterna was observed. The active zone and the vesicular gap-structure of the synapse are discussed.