Profiles of resting potentials across the stria vascularis in kanamycin-deafened guinea pigs

The resting potentials of the marginal cells in the stria vascularis of the guinea pig were determined from changes in the combined electrode-tissue resistance of the electrode. The resistance of the electrode was 45.5±16.0 MΩ (n=20) before penetration of the stria vascularis and 46.7±17.3 MΩ (n=20) after penetration. The resistance drops across the luminal membrane of the marginal cells were 46.0±22.6 MΩ (n=12) in kanamycin-deafened guineal pigs and 54.5±33.1 MΩ (n=9) in normal guinea pigs. The endocochlear potential (EP) and resting potentials in the marginal cells were 90.1±6.0 mV (n=14) and 70.4±11.3 mV (n=14) in kanamycin-deafened guinea pigs and 84.8±5.1 mV (n=29) and 74.7±11.7 mV (n=29) in normal guinea pigs. The resting potentials in the marginal cells decreased gradually and were approximately 0 mV around 20 min after anoxia in both kanamycin-deafened and normal guinea pigs. These changes were comparable to those of EP in kanamycin-deafened guinea pigs during anoxia. The mechanism of the EP in kanamycin-deafened guinea pigs is discussed.