音響刺激後のコルチ器聴毛間連結機構の変化

Abstract

Changes in the glycocalyx structure and ciliary interconnections of the organ of Corti were demonstrated after acoustic overstimulation. A special high resolution scanning electron microscope and a tannic acid-osmium staining technique giving an almost three-dimensional view were used for this demonstration. Guinea pigs were exposed to a 3.85kHz pure tone at an intensity of 120dB for 22.5min. It was possible to observe the early changes of the ciliary interconnections of the hair cell stereocilia. The first detectable change was a disarrangement of the cilia with a loosening of the interconnections. The ciliary membrane had an abnormally smooth appearance. The tip links connecting the tips of the stereocilia to their neighbours were also affected showing elongation or even disappearance. The fine granules which cover the tips of the tallest stereocilia of outer hair cells were also decreased. These findings suggest that acoustic overstimulation probably affects carbohydrate metabolism which induces a regeneration of ciliary interconnections resulting in a disarrangement and detachment of cilia. The tip links, which appeared to be involved in sensory cell transduction, seem also to be affected by acoustic overstimulation.