mRNA encoding 'ClC-K1, a kidney Cl^-- channel' is expressed in marginal cells of the stria vascularis of rat cochlea: Its possible contribution to Cl^- currents

The cochlear stria vascularis is essential for the normal function of hair cells. mRNA encoding the ClC-K1 Cl^- channel, previously thought to be found only in the kidney, was detected in epithelial marginal cells of the rat stria vascularis by single cell RT-PCR. When Cl^- currents were recorded from rat marginal cells by the whole-cell patch clamp method, the steady-state currents showed weak outward rectification and an ion selectivity sequence of SCN^->Br^-=Cl^->F^->NO₃^->I^->gluconate^-. The Cl^- currents were regulated by extracellular Ca²⁺ and pH. These characteristics resemble those reported for the currents recorded from Xenopus oocytes expressing ClC-K1 Cl^- channels. These data together suggest that ClC-K1 Cl^- channels may contribute to the whole-cell currents of marginal cells. Copyright (C) 2000 Elsevier Science Ireland Ltd.