[Effect of potassium canrenoate on the EP and Na+, K+ activities in endolymph]

The perilymphatic space was perfused with artificial perilymph containing 5 x 10(-3)M potassium canrenoate. The EP, K+ and Na+ activities in the scala media were measured with double barrelled K+ or Na+ selective microelectrode. Following the onset of the perfusion, the EP gradually declined and was stable after about 20 minutes. K+ activity also declined gradually but Na+ activity was unchanged. When the EP became stable, the artificial ventilation was stopped. The EP dropped to a large negative potential and K+ activity decreased gradually, but Na+ activity increased by degrees. The same results were observed in the untreated animals when the ventilation was stopped. There are no pathological changes both in the TEM view of the stria vascularis and in the SEM view of the hair cell. These results suggest that this drug may affect K+ conductance of the stria vascularis specifically.