Metabolic disorder of otoconia and the vestibular dark cells.

Abstract

Effects of streptomycin on the otolithic organs were studied in guinea pigs by means of the scanning electron microscope. The most severe damage was found in the otoconia on the otolithic membrane. The layer of the otoconia on the otolithic membrane became thinner at the striola region. The longer the duration of streptomycin injection the fewer were the tiny otoconia evident in the otolithic membrane, and large otoconia remained on this membrane.
The small otoconia were found on vestibular dark cells. The otoconia on the vestibular dark cells were irregular, shrunken or fragmented. Their calcium content, measured with an X-ray micro-analyzer, was diminished in varying degrees. The vestibular dark cells are considered to have pinocytotic activity.
The surface structure of the endolymphatic sac was also observed. According to our morphological findings, three portions were recognized, the proximal, intermediate (rugous) and distal parts. Morphological changes of endolymphatic sac cells were no ed in the intermediate portion.