The consistent occurrence of a striated organelle (Friedmann body) in the inner hair cells of the normal chinchilla.

Striated organelles have consistently been observed in electron micrographs of serial sections from the inner hair cells of normal chinchilla cochleas. The striated organelle is located in the infracuticular plate region. It lines the cuticular plate, and the direction, pattern and periodicity of the striations vary along its length. The striated organelle is seen in close association with the cell membrane, smooth endoplasmic reticulum, microtubules and mitochondria. The striated organelle may play an active role in inner hair cell function, and its proliferation under pathological conditions, as observed by others, may be accompanied by alterations in sensitivity of the inner hair cell to stimuli.