Figure 2

The mechanically activated current is a non-selective cation current. (A) Representative traces of mechanotransduction currents evoked by identical mechanical stimuli (probe velocity 4.3 mm/s) from a DRG neuron with a soma diameter of 36 μm. Membrane potential was stepped for 1 s to voltages ranging from -110 to +130 mV in steps of 20 mV, 720 ms prior to mechanical stimulation. Every other trace is omitted for clarity. (B) Mean amplitudes of currents evoked by mechanical stimulation of DRG neurons (n = 20) bathed in the normal external solution and using cesium sulfate/cesium chloride electrode solution. The mean amplitude at -70 mV was -436 ± 145 pA and the mean reversal potential was 25 ± 4 mV. (C) Comparison of I-V data for the 4 smallest (<35 μm, closed squares) and 6 largest (>40 μm, open squares) diameter DRG neurons in standard solutions. The two curves are not significantly different from each other, using a 2-way ANOVA test. (D) Mean amplitudes of currents evoked by mechanical stimulation of DRG neurons in the normal external bath solution while using electrodes filled with cesium and the impermeant anion methanesulfonate (n = 6). The mean reversal potential was 23 ± 5 mV.