Molecular and Physiological Bases of the K+ Circulation in the Mammalian Inner Ear

Hiroshi Hibino and Yoshihisa Kurachi Department of Pharmacology, Division of Molecular and Cellular Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan, ykurachi{at}pharma2.med.osaka-u.ac.jp Endolymph, the extracellular solution in cochlea, contains 150 mM K + and exhibits a potential of approximately +80 mV relative to neighboring extracellular spaces. This unique situation, essential for hearing, is maintained by K + circulation from perilymph to endolymph through the cochlear lateral wall. Recent studies have identified ion-transport molecules involved in the K + circulation and their pathophysiological relevance.