Longitudinal flow of endolymph measured by distribution of @entity5128 and XXXX in scala media.

@entity1041 @entity5128 @entity840 @entity1877 @entity972 @entity2798
Longitudinal endolymph flow rate in the @entity840 cochlea was measured by determining the rate of migration of extrinsic ions, @entity5128 ( @entity1041 ) or @entity1877 , with a @entity972 sensitive @entity2798 ( @entity2798 ). Low concentrations of iontophoretically injected @entity1041 were detected with the @entity2798 at various distances from the injection electrode. The results were variable when the @entity2798 was used to record spread of @entity1041 from turn II to turn I and vice versa. However, consistent data were obtained when the @entity1041 spread was measured at different electrode separations (0.2, 0.5, 0.7 mm) within turn II. Electrode locations were systematically exchanged without changing their distance, i.e. the @entity2798 electrode was placed basally or apically with respect to the @entity1041 electrode. Comparison of data with a model, which combines the bulk diffusion of @entity1041 and the flow of endolymph, is consistent with a rate of endolymph flow in turn II of about 0.2 mm/min, apex to base. A similar value was also obtained with the iontophoretic injection of @entity1877 . The endolymph flow rate may be different in turn I as indicated by measurements of compound action potential (CAP) changes. However, the results of experiments when @entity1041 spread is measured at large distances must be interpreted cautiously because @entity1041 may enter cellular walls of the cochlear duct and alternative routes of transport may be involved.
