RT Journal Article
SR Electronic
T1 Phase tracking algorithms detect both real and imaginary components of outer hair cell nonlinear membrane capacitance that exhibits dielectric loss
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2022.01.01.474702
DO 10.1101/2022.01.01.474702
A1 Joseph Santos-Sacchi
YR 2022
UL http://biorxiv.org/content/early/2022/01/11/2022.01.01.474702.abstract
AB Outer hair cell (OHC) nonlinear membrane capacitance (NLC) represents voltage-dependent sensor charge movements within prestin (SLC26a5) that drive OHC electromotility. Dielectric loss, a shift in charge movement phase from purely “capacitive” to “resistive”, is likely indicative of prestin’s interaction with the viscous lipid bilayer and has been suggested to correspond to prestin power output. The frequency response of NLC in OHC membrane patches has been measured with phase tracking and complex capacitance methodologies. While the latter approach can directly determine the presence of dielectric loss by assessing charge movement both in and out of phase with driving voltage, the former has been suggested to fail in this regard. Here we show that standard phase tracking in the presence of dielectric loss does indeed register this loss. Such estimates of NLC correspond to the absolute magnitude of complex NLC, indicating that total charge movement regardless of phase is assessed, thereby validating past and present measures of NLC frequency response that limits its effectiveness at high frequencies. This observation has important implications for understanding prestin’s role in cochlear amplification.Competing Interest StatementThe authors have declared no competing interest.