Reversible Inhibition of Voltage-dependent Outer Hair Cell Motility and Capacitance

摘要: Outer hair cells (OHC) from the organ of Corti are capable fast voltage-induced length changes (Santos-Sacchi and Dilger, 1988), suggesting that an associated voltage sensor should reside in OHC plasma membrane. Voltage-dependent mechanical responses nonlinear charge movement isolated OHCs guinea pig were analyzed using whole-cell voltage-clamp technique. Ionic currents blocked. Nonlinear voltage-dependent or, correspondingly, capacitance was measured with step or AC analysis. movements either video a differential photodiode Maximum up to 2.5 pC low-frequency region cochlea. Both analyses indicated peak 16- 17 pF. The dependence fit Boltzmann relation analysis indicating maximum at -23 mV potential holding about -120 mV, near -40 mV. probably provides more accurate evaluation dependence. Measures motility magnitude versus follow capacitance-voltage function obtained measures. Treatment gadolinium ions (0.5-1 mM) blocked motility. This treatment also produced shift along axis depolarizing direction, which can be explained by membrane surface screening. However, reduced as well may correspond reduction abolition response treatment. Gadolinium effects reversible. is not deformation due changes, since removal cytosol via patch pipette abolished longitudinal but did reduce movement. It interesting note will dynamically influence time constant during acoustically evoked receptor generation.