A family of currents from a single cell illustrates the voltage dependence of channel inactivation, with severely slowed decay times at positive voltages ( middle). (C) Voltage step protocol with a single “poke” displacement during each step ( left). Data are from Lewis and Grandl, unpublished. Typically, currents do not plateau before cell rupture ( below). From these experiments, a current-displacement curve can be generated. Piezo1 current amplitudes increase with increasing steps of displacement beginning a few micrometers beyond first contact of the probe with the cell membrane. (B) Schematic of “poke” setup depicting cell deformation by a blunt probe (typically a fire-polished glass pipette) during a whole-cell recording, which activates a larger population of channels throughout the cell ( above). Data are from Wu and Grandl, unpublished. The pressure-response relationship can be fit with a sigmoidal function to measure pressure sensitivity ( below).
Piezo1 peak current amplitudes initially rise with increasing magnitudes of pressure before reaching saturation ( middle).
#Classical stretch Patch#
(A) Schematic of “stretch” setup, in which negative suction is applied to a cell-attached patch with a high-speed pressure clamp through the patch pipette, stimulating only those channels contained within the patch dome ( above). Piezos are mechanically activated ion channels
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