[The morphologic changes of outer hair cells induced by hypotonic, hypertonic medium and electromotility].

For further understanding of biological features of cochlear outer hair cells, outer hair cells were isolated from guinea pig cochlea with micromechanical method and observed when the microosmotic concentration of their culture medium were changed. Outer hair cells shortened 3.14 +/- 0.76% (P < 0.01) within one minute after the osmotic concentration of the medium decreased to 280 mmol/L, accompanied with increase of cell diameter. Elongation of 3.34 +/- 1.09% (P < 0.05) of outer hair cells were observed after osmotic concentration of the medium was increased to 320 Os mmol/L, accompanied with decrease of cell diameter. Oscillatory elongation and shortening of outer hair cells and oscillatory displacements of intracellular organelles could be observed when square wave electrical potentials were applied across isolated outer hair cells. Hypertonic high potassium medium (K+ 100 mmol/L, 320 Osmmol/L) decreased the oscillatory movement of the cells by about 43.14% (negative potential) and 46.17% (positive potential) (P < 0.05). The shape of outer hair cells restored when the medium was isotonic. The mechanism and biological bases of outer hair cell movement were discussed.