Oxygen reserve and autoregulation in the cochlea.

Endolymphatic O2-concentration was measured in the guinea pig cochlea with a microelectrode inserted through the zona pectinata of the basilar membrane and the cells of Claudius, so as not to interfere with the blood supply to the organ of Corti. The O2-level and the amplitude of the cochlear potentials were followed during hypoxia produced by lowering the pO2 of the inspired air. Persistence of a normal endolymphatic O2-level following the fall in arterial pO2 indicated an O2-reserve and au autoregulation of the cochlear circulation.