Effect of Chloride Deficiency on Cochlear Potentials

Abstract

The scala tympani or scala media in guinea pigs was perfused with Ringer-Locke's solution (in the case of the scala media, potassium-rich Ringer's solution) in which chloride was replaced with ferrocyanide, nitrate, glutamate, or acetate. Cochlear microphonics (CM), summating potential (SP), action potential (AP), and endocochlear potential (EP) were recorded from the basal turn before, during, and after the perfusion. Chloride lack in the endolymph did not alter the cochlear potentials, including EP, immediately. Perfusion of the scala tympani with acetate-Ringer's solution caused reversible depression of CM and temporary increase of AP followed by gradual depression. The dc polarization persisted even after chloride ions were removed from the perilymph by introduction of chloride-free solution into the scala tympani. The relationship between the cochlear potentials and the cochlear fluid is discussed. [Work supported by a grant from the National Institute of Neurological Diseases and Blindness, National Institutes of Health, Public Health Service, U. S. Department of Health, Education, and Welfare.]