mRNA expression of kidney-specific ClC-K1 chloride channel in single-cell reverse transcription-polymerase chain reaction analysis of outer hair cells of rat cochlea.

Outer hair cells (OHCs) of cochlea have been suggested to have Cl(-) channels sensitive to an ototoxic diuretic, furosemide. We therefore examined whether kidney-specific chloride channels (ClC-K1 and ClC-K2) and ClC-5 are also expressed in OHCs of rat cochlea, assuming that these channels might be the targets of oto-nephrotoxic drugs, by single-cell reverse transcription-polymerase chain reaction (RT-PCR) technique. Single-cell RT-PCR revealed the presence of transcripts of ClC-K1 in OHCs which was verified by DNA sequencing, while ClC-K2 and ClC-5 were not detected. The possible roles of ClC-K1 in OHCs are discussed.