INDUCED MEMBRANE HYPO/HYPER-MECHANOSENSITIVITY:A Limitation of Patch-Clamp Recording

Practical limitations of the patch-clamp technique when recording mechanogated membrane ion channels are considered. Mechanical overstimulation of the patch or the cell from excessive suction/pressure protocols induces morphological and functional changes. In particular, the plasma membrane becomes decoupled from the underlying cytoskeleton to form either membrane blebs (cell-attached) or ghosts (whole cell). As a consequence, a membrane ion channel may show either a decrease or an increase in its native mechanosensitivity or even acquire mechanosensitivity. The effect varies with ion channel and cell type and presumably arises because of a disruption of membrane-cytoskeleton interactions. We consider that such disruptions are a pathological consequence of excessive mechanical stress, either during or after seal formation, rather than an immutable consequence of patch-clamp recording. By careful attention to the suction/pressure protocols during sealing and throughout recording, such artifacts can be avoided.