The Effects Of Ethacrynic Acid Upon The Cochlear Endolymph And Stria Vascularis: A Preliminary Report

Abstract

The normal endocochlear potential was rapidly replaced by a negative anoxic-type potential after ethacrynic acid administration (60 mg/kg) in the rat. Recovery at first proceeded quickly but became very much slower at 30 min. However, the endolym-phatic chemical composition remained unaltered until 35 min, when progressive increase in the sodium and decrease in the potassium concentrations occurred, followed at 1 hour by a gradual return towards normal. Thus the drug probably causes transient inhibition of the strial enzymes and then abnormalities in membrane permeability. The characteristic accumulation of inter-cellular fluid in the stria vascularis was associated with and seemed to arise from these permeability changes. In addition, the findings strongly support the concept that the endocochlear potential has two components, a positive secretion potential and a negative potassium diffusion potential.