Directional rectification of gap junctional voltage gating between Dieters cells in the inner ear of guinea pig

Deiters cells (DCs) are the cochlear supporting cells in inner ear and contain multiple gap junction connexin genes, which when mutated can induce hearing loss. In the present study, the gap junctions between DCs were investigated by a double voltage clamp technique. Besides asymmetric responses to the polarities of transjunctional voltage (V(j)) and transmembrane potential (V(m)), the channels were also sensitive to which cell side was stimulated in a cell pair, i.e. voltage gating had directional dependence. The direction-dependent voltage gating could result in asymmetric current flow between the cells and influenced K⁺ passage. Multiple connexins may constitute non-homotypic channels with directional dependence of voltage gating to mediate functional gap junction pathways in the cochlea. This may explain how a single connexin mutation can produce hearing loss. (C) 2000 Elsevier Science Ireland Ltd.