Ouabain is a selective and potent inhibitor of the plasma membrane Na+/K+-ATPase pump.In vivo studies in gerbil and mice have found that round window application of ouabain selectively destroys type Ⅰ spiral ganglion neurons,but has little effect on hair cells possibly due to the fact that the round window membrane lies adjacent to the spiral ganglione in the basal turn of the cochlea.The aim of our study is to elucidate the effects of ouabain on the rat inner ear in vitro and in vivo,a species widely used in research.