Experimental studies on the role of vitamin A in the inner ear.

With the sole exception of the hair cells of the inner ear, where information is lacking, all special somatic afferent receptor cells have been shown to be dependent upon vitamin A for normal function. In view of the paucity of information on the role of vitamin A in the inner ear, three experiments were performed to examine this relationship. Temporal bone histopathology was studied in rats deprived of vitamin A. In a second experiment, vitamin A-deficient rats were maintained with vitamin A acid and the histopathology was studied under the light microscope. In the third experiment, a microfluorometric estimate of the content of vitamin A in the guinea pig cochlea was performed. A fluorescent compound with the exact spectral characteristics of vitamin A was found in the guinea pig cochlea at a concentration of 21.2 micrograms/gm, which is ten times the vitamin A concentration found in most other tissues.