Maintenance of Cochlear Potentials During Asphyxia

Abstract

The perilymphatic space of the guinea pig cochlea was perfused with a variety of solutions which differed in O₂ content and K+ concentration. Perfusion either preceded asphyxia and continued during the asphyxia interval or it followed by several minutes the onset of asphyxia and continued concomitantly with asphyxia for several additional minutes. Perfusion of scala vestibuli served to maintain EP, CM and SP at relatively high levels when perfusion preceded asphyxia. The potentials were partially restored when perfusion followed asphyxia. Perfusion of scala tympani, on the other hand, was without effect. So far as we could determine, the various perfusates did not have a differential influence on cochlear potentials. It appeared that perfusion rate was the critical variable with maintenance in the potentials being positively related to flow rate. We did not have this rate variable under strict experimental control. We proposed that the primary role of perfusion was to remove from the cochlea toxic agents that accumulated during anaerobic metabolism. This, in turn, led to the saltatory effects on cochlear potentials.