A possible site of production of the negative endocochlear DC potential

The scala vestibuli or the scala tympani of guinea pigs was perfused with artificial perilymph containing 1, 5, 10, 20, 30, 40 and 50 mM of potassium chloride in a total concentration of 150 mM with the background composed of sodium chloride. With the perfusion of the scala vestibuli, each concentration failed to alter the magnitude of the negative endocochlear DC potential produced by anoxia or the intravenous injection of 100 mg/kg of body weight of furosemide. With the perfusion of the scala tympani, the negative endocochlear DC potential disappeared precipitously and the maximum output of the cochlear microphonic was severely depressed with concentrations of potassium chloride of 30 mM or greater. The magnitude of the negative endocochlear DC potential appears to be closely related to the maximum output of the cochlear microphonic. These results suggest that the site of production of the negative EP is in the hair cells of the organ of Corti.