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Published on: September 14, 2012
Voltage-induced membrane displacement in patch pipettes activates mechanosensitive channels
Z Gil1, S D Silberberg, K L Magleby
1Department of Life Sciences, The Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel.
Summary
Prolonged depolarization in patch-clamp recordings causes membrane displacement, activating mechanosensitive channels. This tension, not voltage, may explain apparent channel voltage-dependence.
Area of Science:
- Cellular electrophysiology
- Ion channel biophysics
- Membrane mechanics
Background:
- The patch-clamp technique is crucial for studying ion channel function.
- Voltage application is standard for probing channel gating and voltage-sensitivity.
- Potential artifacts in patch-clamp recordings can affect experimental interpretations.
Purpose of the Study:
- To investigate the relationship between prolonged depolarization and membrane mechanics in patch-clamp recordings.
- To determine if membrane displacement influences mechanosensitive (MS) channel activity.
- To clarify the origins of apparent voltage-dependence in ion channel recordings.
Main Methods:
- Utilized video microscopy and single-channel recording in patch-clamp experiments.
- Applied prolonged voltage depolarization to membrane patches in borosilicate pipettes.
- Manipulated membrane displacement using positive pressure and pipette tip coatings.
Main Results:
- Prolonged depolarization induced delayed, slow membrane displacement into the pipette.
- This membrane displacement was temporally correlated with the activation of mechanosensitive channels.
- Preventing displacement abolished depolarization-induced MS channel activation, indicating tension as the trigger.
Conclusions:
- Voltage-induced membrane tension, not direct voltage modulation, can activate MS channels.
- Apparent voltage-dependence of channels/transporters may arise from membrane tension artifacts.
- This finding necessitates re-evaluation of voltage-clamp interpretations, especially with borosilicate pipettes.
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