Vascular perfusion of the cochlea: effect of potassium-free and rubidium-substituted media

By means of vascular perfusion of the cochlea with K+-free synthetic blood, it is possible to maintain the endocochlear potential (EP) at normal or supernormal levels for periods of 20-42 min. The subsequent decline of the EP is comparatively slow. This is in contrast to the immediate onset and rapid decline of the EP during perilymphatic perfusion with K+-free media. Possible implications of these data concerning the mode of generation of the EP are briefly discussed. It is further shown, that synthetic blood, in which K+ is replaced by Rb+, maintains the EP at normal or near normal levels for 2 h.