Distortion component analysis of outer hair cell motility-related gating charge.

摘要: The underlying Boltzmann characteristics of motility-related gating currents the outer hair cell (OHC) are predicted to generate distortion components in response sinusoidal transmembrane voltages. We studied this since it reflects mechanical activity that may contribute peripheral auditory system distortion. Distortion OHC electrical were analyzed using whole-cell voltage clamp technique, under conditions where ionic conductances blocked. Single or double-sinusoidal stimulation was delivered at various holding voltages, and current responses detected by Fourier analysis. Current magnitude phase each component as a function membrane potential compared with voltage-dependent capacitance, obtained stair-step transient analysis dual-frequency admittance sum most prominent among all Notches (f1+f2), difference (f2−f1) second harmonic (2f) occur peak capacitance resides (VpkCm). Rapid reversals also occurred VpkCm, but remained fairly stable more depolarized hyperpolarized potentials. Thus, is possible extract parameters charge movement from these components. In fact, we have developed technique follow changes dependence motility tracking reversal f2−f1 product. When intracellular turgor pressure changed, VpkCm notch voltages shifted same direction. These data important implications for understanding cochlear nonlinearity, generally, indicate usefulness study displacement currents.