Inward-rectifier chloride currents in Reissner’s membrane epithelial cells

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• 作者：Kyunghee X. Kim ; Daniel C. Marcus
• 关键词：Cl⁻ ; channel ; Epithelial transport ; Cochlea ; ClC-2 channel
• 刊名：Biochemical and Biophysical Research Communications
• 出版年：2010
• 出版时间：2 April 2010
• 年：2010
• 卷：394
• 期：2
• 页码：434-438
• 全文大小：337 K

文摘

Sensory transduction in the cochlea depends on regulated ion secretion and absorption. Results of whole-organ experiments suggested that Reissner’s membrane may play a role in the control of luminal Cl⁻. We tested for the presence of Cl⁻ transport pathways in isolated mouse Reissner’s membrane using whole-cell patch clamp recording and gene transcript analyses using RT-PCR. The current–voltage (I–V) relationship in the presence of symmetrical NMDG-Cl was strongly inward-rectifying at negative voltages, with a small outward current at positive voltages. The inward-rectifying component of the I–V curve had several properties similar to those of the ClC-2 Cl⁻ channel. It was stimulated by extracellular acidity and inhibited by extracellular Cd²⁺, Zn²⁺ and intracellular ClC-2 antibody. Channel transcripts expressed include ClC-2, Slc26a7 and ClC-Ka, but not Cftr, ClC-1, ClCa1, ClCa2, ClCa3, ClCa4, Slc26a9, ClC-Kb, Best1, Best2, Best3 or the beta-subunit of ClC-K, barttin. ClC-2 is the only molecularly-identified channel present that is a strong inward rectifier. This study is the first report of conductive Cl⁻ transport in epithelial cells of Reissner’s membrane and is consistent with an important role in endolymph anion homeostasis.