Chloride Dependent Coupling of Molecular to Cellular Mechanics in the Outer Hair Cell of Corti's Organ

摘要

Within the OHC lateral membrane, conformational changes in the motor protein prestin are driven by voltage induced displacements of intrinsic, charged moieties that can be monitored by measures of the cell's nonlinear capacitance. The cellular expression of these summed molecular events is a robust electromotility of the whole cell. We now find that the coupling of molecular to cellular mechanics is dependent on intracellular chloride levels, where normal levels (<10 mM) do not support tight coupling between the two. Thus, in vivo, electromotility is predicted to be poorly coupled to changes in OHC receptor potentials, whereas molecular conformational change is tightly coupled. We suspect that membrane mechanical characteristics driven by prestin may more significantly govern cochlea amplification than electromotility.