Abstract
Eighteen pigmented rabbits were used for this study. Following obliteration of the endolymphatic sac, the vestibular function was examined by caloric and rotatory tests, and the fine structure of the crista ampullaris of the horizontal semicircular canal and macula utriculi was observed by transmission electron microscopy. The caloric response was reduced in 7 cases. No change was detected by the rotatory test in any of the cases. Spontaneous deviation of the head was observed in one case. Vacuolization, swelling or disruption of mitochondria were found in the hair cells and suppotring cells of the macula utriculi in 14 cases. These same structural changes were found in the hair cells and supporting cells of the crista ampullaris in 9 cases, which also showed a higher rate of hypoactive caloric responses than the other cases. The degeneration of the macula utriculi and crista ampullaris always occured simultaneously with endolymphatic hydrops.
