Expression and localization of the Na-K-2Cl cotransporter in the rat cochlea.

We identified the localization of the basolateral bumetanide-sensitive Na-K-2Cl cotransporter (BSC2) in the cochlea using an in situ hybridization method. In the rat cochlea, the BSC2 mRNA was mainly expressed in the strial marginal cells. Although the fibrocytes localized at the spiral prominence showed a weak expression of BSC2 mRNA, no expression was observed in the organ of Corti or spiral ganglion cells. The present findings are well consistent with a proposed cell model of ion transport in the marginal cell.