Fig. 2

Inactivation and desensitization of PIEZO1 can be reset by outward permeation. Repetitive pressure stimulations desensitize PIEZO1 at −60 mV (a) but not at +60 mV (b). Note the decreased peak current and low peak/steady-state current ratio at −60 mV. c Alternating pressure pulses at −60 mV and +60 mV abolishes desensitization and prevents PIEZO1 from entering a non-inactivating state. d Peak currents in a (negative pulses), b (positive pulses) and c (negative pulses) were normalized to the first response and plotted against time. Desensitization is absent at alternating voltages. e Three pressure pulses (P1, P2, P3) at −60 mV were applied to patches expressing PIEZO1 to drive the channel into a desensitized state, followed by one positive pressure pulse (P4) at +40 mV. The sequence was repeated twice. Outward permeation (P4) recovers PIEZO1 initial current (P1), as shown by the ratio of P5/P1, shown in h). f The stimulation sequence in e was repeated in absence of pressure at P4. The recovery from desensitization does not occur at +40 mV in absence of permeation. g The same protocol in Fig. 2e was repeated with the ionic concentrations shown. Inward currents flow at P4 at +40 mV. No recovery from desensitization is observed at P5, underlining the importance of outward permeation for resetting channel kinetics. h The P5/P1 ratio for e (white, n = 10), f (green, n = 13), and g (orange, n = 7) are shown and are statistically different (Anova, Dunnett’s post-hoc test, dF = 18, white vs green P = 0.00004, white vs orange P = 0.001). i Raw amplitude levels for P4 in f (green) or g (orange) are statistically different (Student’s t-test P = 0.00003, dF = 20). j Paired pulses protocol of a pressure stimulus at +60 mV preceded by either a pressure step at −60 mV (light blue) or at +60 mV (black). The direction of the first current stimulus affects the amplitude and the time course of activation of an identical second step at +60 mV. k The rise time and the amplitude ratio of the second stimulus at +60 mV in j are compared. The interval between the two stimuli was either 2 or 30 s. Both parameters are significantly different (Students t-test P < 0.001, n = 28, dF = 26). The data are shown as mean ± SEM