| Publication . | Method to evoke and measure load-free eM . | Frequency response cut-off . | Voltage delivery and/or eM measurement limitations . | Notes . |
|---|---|---|---|---|
| (Kachar et al., 1986) | Transcellular AC current; standard video | No estimate of roll-off; 1–30 Hz frame rates. | Rm * Cm time constant; limited to 60 frames/s | |
| (Ashmore, 1987) | Whole-cell voltage clamp; photodiode | Dual Lorentzian cut-offs at 67 and 664 Hz | Voltage clamp Rs * Cm time constant | |
| (Santos-Sacchi, 1992) | Whole-cell voltage clamp; photodiode | Single Lorentzian cut-off at 1 kHz | Voltage clamp Rs * Cm time constant | |
| (Reuter et al., 1992) | Transcellular AC current stimulation in organ explants; stroboscopic video | 40 dB down at 15 kHz | Membrane Rm * Cm time constant | |
| (Dallos and Evans, 1995) | Microchamber cell partitioning, AC voltage from low-impedance waveform generator; photodiode | No estimate of roll-off, as shape of frequency response is a function of apical to basal impedances; eM detection above 10 kHz; zero microchamber V offset | Rs * Cin (input capacitance of partitioned cell) for command voltage; ratio of partitioned impedance modifies roll-off shape | Low frequency eM gain:∼5 nm/mV indicative of offset away from Vh; no estimation of V delivery roll-off based on generated currents |
| (Gale and Ashmore 1997b) | On-cell and excised membrane patch under voltage clamp | Patch movements (≈ eM) measured with step voltages; 10 kHz cut-off for patch NLC; 0.19× lower cut-off for movements | Near ideal voltage clamp | First indication that eM and NLC frequency response may differ |
| (Frank et al., 1999) | Microchamber cell partitioning; voltage clamp; laser Doppler vibrometer | Variable cut-off; for 30 µm cell extrusion 33 kHz; smaller extrusions > 70 kHz; zero microchamber V offset | Rs * Cin for command voltage; ratio of partitioned impedance modifies roll-off shape | Low frequency eM gain:∼5 nm/mV indicative of offset away from Vh; voltage corrections based on Rs * (stray || membrane capacitance) |
| (Kitani et al., 2011) | Transcellular AC current; video analysis at 18 kHz | Responses measured up to 4 kHz | Rm * Cm time constant | Time dependent changes in eM magnitude may be attributed to mechanisms other than prestin |
| (Santos-Sacchi and Tan, 2018) | Microchamber cell partitioning; voltage clamp; video analysis at 50 KHz frame rate | At microchamber V offset to Vh, dual Lorentzian cut-offs of 33 Hz and 6.3 kHz; at zero microchamber V offset, dual Lorentzian cut-offs of 234 Hz and 8.7 kHz | Rs * Cin for command voltage; ratio of partitioned impedance modifies roll-off shape | Low frequency eM gain (at Vh): 16.8 nm/mV; voltage corrections based on exponential current decays during V stimulation at two microchamber offsets; eM measures made under whole cell voltage clamp were not corrected for delivery roll-off |
| Publication . | Method to evoke and measure load-free eM . | Frequency response cut-off . | Voltage delivery and/or eM measurement limitations . | Notes . |
|---|---|---|---|---|
| (Kachar et al., 1986) | Transcellular AC current; standard video | No estimate of roll-off; 1–30 Hz frame rates. | Rm * Cm time constant; limited to 60 frames/s | |
| (Ashmore, 1987) | Whole-cell voltage clamp; photodiode | Dual Lorentzian cut-offs at 67 and 664 Hz | Voltage clamp Rs * Cm time constant | |
| (Santos-Sacchi, 1992) | Whole-cell voltage clamp; photodiode | Single Lorentzian cut-off at 1 kHz | Voltage clamp Rs * Cm time constant | |
| (Reuter et al., 1992) | Transcellular AC current stimulation in organ explants; stroboscopic video | 40 dB down at 15 kHz | Membrane Rm * Cm time constant | |
| (Dallos and Evans, 1995) | Microchamber cell partitioning, AC voltage from low-impedance waveform generator; photodiode | No estimate of roll-off, as shape of frequency response is a function of apical to basal impedances; eM detection above 10 kHz; zero microchamber V offset | Rs * Cin (input capacitance of partitioned cell) for command voltage; ratio of partitioned impedance modifies roll-off shape | Low frequency eM gain:∼5 nm/mV indicative of offset away from Vh; no estimation of V delivery roll-off based on generated currents |
| (Gale and Ashmore 1997b) | On-cell and excised membrane patch under voltage clamp | Patch movements (≈ eM) measured with step voltages; 10 kHz cut-off for patch NLC; 0.19× lower cut-off for movements | Near ideal voltage clamp | First indication that eM and NLC frequency response may differ |
| (Frank et al., 1999) | Microchamber cell partitioning; voltage clamp; laser Doppler vibrometer | Variable cut-off; for 30 µm cell extrusion 33 kHz; smaller extrusions > 70 kHz; zero microchamber V offset | Rs * Cin for command voltage; ratio of partitioned impedance modifies roll-off shape | Low frequency eM gain:∼5 nm/mV indicative of offset away from Vh; voltage corrections based on Rs * (stray || membrane capacitance) |
| (Kitani et al., 2011) | Transcellular AC current; video analysis at 18 kHz | Responses measured up to 4 kHz | Rm * Cm time constant | Time dependent changes in eM magnitude may be attributed to mechanisms other than prestin |
| (Santos-Sacchi and Tan, 2018) | Microchamber cell partitioning; voltage clamp; video analysis at 50 KHz frame rate | At microchamber V offset to Vh, dual Lorentzian cut-offs of 33 Hz and 6.3 kHz; at zero microchamber V offset, dual Lorentzian cut-offs of 234 Hz and 8.7 kHz | Rs * Cin for command voltage; ratio of partitioned impedance modifies roll-off shape | Low frequency eM gain (at Vh): 16.8 nm/mV; voltage corrections based on exponential current decays during V stimulation at two microchamber offsets; eM measures made under whole cell voltage clamp were not corrected for delivery roll-off |