Ion transport in the cochlea of guinea pig. II. Chloride transport.

The -Cl transport of endolymph--perilymph barrier in guinea pigs was studied by perfusing the perilymphatic space with artificial perilymph containing 36Cl and measuring the uptake of 36Cl in the endolymph. In normal animals no marked difference in -Cl concentration was found between the endodlymph and perilymph. The data showed that the uptake of 36Cl in the endodlymph could be represented by a simple exponential function of the perfusion time, the rate constant being 0.01 min-1. The concentration of 36Cl in the endolymph was greater with perfusion of the scala vestibuli than with perfusion of the scala tympani, indicating the Reissner's membrane is more permeable to -Cl than the rest of the endolymph-perilymph barrier. Anoxia and local application of ouabain decreased the -Cl concentration and 36Cl uptake in the endolymph. Our results imply that the endocochlear potential is the principal driving force for unidirectional flux of -Cl from perilymph to endolymph.