mRNA encoding 'CIC-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 CIC-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 CIC-K1 Cl- channels. These data together suggest that CIC-K1 Cl- channels may contribute to the whole-cell currents of marginal cells. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.