Figure 6.

Na⁺-selective transepithelial transport by Reissner's membrane. Na⁺ from endolymph enters the cell across the apical membrane through an amiloride- and benzamil-sensitive cation channel that excludes K⁺. Na⁺ in the cytosol is extruded across the basolateral membrane into perilymph of scala vestibuli by the Na⁺-pump (Na⁺, K⁺-ATPase). K⁺ entering the cell by the pump is passively extruded across the basolateral membrane via K⁺ channels.