Voltage-induced membrane displacement in patch pipettes activates mechanosensitive channels

Ziv Gil, Shai D. Silberberg, Karl L. Magleby

Research output: Contribution to journalArticle

22 Scopus citations

Abstract

The patch-clamp technique allows currents to be recorded through single ion channels in patches of cell membrane in the tips of glass pipettes. When recording, voltage is typically applied across the membrane patch to drive ions through open channels and to probe the voltage-sensitivity of channel activity. In this study, we used video microscopy and single-channel recording to show that prolonged depolarization of a membrane patch in borosilicate pipettes results in delayed slow displacement of the membrane into the pipette and that this displacement is associated with the activation of mechanosensitive (MS) channels in the same patch. The membrane displacement, ≃1 μm with each prolonged depolarization, occurs after variable delays ranging from tens of milliseconds to many seconds and is correlated in time with activation of MS channels. Increasing the voltage step shortens both the delay to membrane displacement and the delay to activation. Preventing depolarization-induced membrane displacement by applying positive pressure to the shank of the pipette or by coating the tips of the borosilicate pipettes with soft glass prevents the depolarization- induced activation of MS channels. The correlation between depolarization- induced membrane displacement and activation of MS channels indicates that the membrane displacement is associated with sufficient membrane tension to activate MS channels. Because membrane tension can modulate the activity of various ligand and voltage-activated ion channels as well as some transporters, an apparent voltage dependence of a channel or transporter in a membrane patch in a borosilicate pipette may result from voltage-induced tension rather than from direct modulation by voltage.

Original languageEnglish (US)
Pages (from-to)14594-14599
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume96
Issue number25
DOIs
StatePublished - Dec 7 1999

ASJC Scopus subject areas

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