R6101

Standard whole-cell voltage clamp and mechanical stimulation by a piezoelectric-driven glass probe were used as described previously (11 (link), 21 (link)). Electrodes (Kimble KG12 glass) were pulled by Sutter P97 puller (Sutter Instruments), coated with R6101 (Dow Corning), and fire-polished to 2–5 MΩ. Stimulation and data acquisition were done with an Axopatch 200B patch-clamp amplifier, CyberAmp 320 signal conditioner, Digidata 1550A, and pClamp 10.5 software (Molecular Devices). Whole-cell voltage-clamp signals were sampled at 20 kHz and filtered at 4 kHz. Series resistance was compensated in all whole-cell recordings. Cells held at −120 mV, and voltage-dependent currents were recorded from −80 through +15 mV in 5-mV steps for 50 ms to measure steady-state activation, then stepped to 0 mV for 50 ms to measure steady-state inactivation. The start-to-start time was 250 ms per sweep and 6 s per run for up to 10 runs. Mechanical stimulation was applied as stated in results via fire-polished glass microelectrodes driven by a piezotransducer P-621.1CD attached to an E-625.CR controller (Physik Instrumente). Displacement ladders were 50-ms steps of 0.3-µm increments at a 0.6-µm/ms upstroke/downstroke rate.