Acoustic Trauma in the Guinea Pig: II.Electron microscopy including the morphology of cell junctions in the organ of Corti

Guinea pigs exposed to a pure tone of 500 cycles per second at 128 dB Sound Pressure Level yielded no great ultrastructural changes until threshold shifts in excess of 80 dB were encountered. Above this level gross hair cell injuries were observed. Rupture of the hair cells was apparently preceded by a progressive destruction or loss of the vesiculated membranes from beneath the plasma membrane. There was no evidence of damage to nerve tissues. Cell junctions of the organ of Corti are described. Fused junctions along the Hensen-Deiters' border appear to have separated in animals with a low threshold shift. The junctions in the reticular lamina were completely resistant.