Fig. 3

Increasing outward permeation determines the number of channels available for activation. a A constant pressure pulse at −60 mV was preceded by a constant pressure stimulation (70 mmHg) at increasing voltages (20 mV black, 40 mV green, 60 mV blue, and 80 mV red). The current amplitude of the second pressure stimulation depends on the driving force applied during the preceding step, showing that the larger the applied driving force the greater the relief from inactivation. b The conditioning stimulus voltage was plotted against the normalized current amplitude of the currents recorded at −60 mV. Single cells were fitted individually to a Boltzmann fit. The data shown represent pooled data from  10 cells (V₅₀ = 85.5 ± 5 mV). c Tail current protocol as in Fig. 1d preceded by a conditioning pressure pulse at +100 mV to remove ~80% of inactivation. d Tail currents from individual cells were normalized to their maximum and fitted to a Boltzmann relationship (V₅₀ = 90.6 ± 2.9 mv, slope 24.6 ± 1.6, n = 12 cells without the conditioning step, black trace, V₅₀ = 68.3 ± 10.2 mV, slope 43.7 ± 2.3, 5 cells, with conditioning step at +100 mV, red trace, unpaired Student’s t-test P = 0.0036, dF = 15). Pooled data are shown as mean ± SEM. e Proposed transition between active and inactive state PIEZO1. Activation by pressure (ΔP) and negative electrochemical gradient (−Δμ) drives the channel into an inactive state (domains tilted upward). Pressure and positive electrochemical gradient (+Δμ) reset the channel to an active state by opening an inactivation gate. The transition 3-4-1 is a slow conformational change as suggested by the rise time and amplitude in Fig. 2j, k, l