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Human skeletal muscle has a voltage-gated proton current
R M Krause1, L Bernheim, C R Bader
1Division de Neurophysiologie Clinique, Hôpital Cantonal Universitaire Genève, Switzerland.
Neuromuscular Disorders : NMD
|September 1, 1993
Summary
Human muscle cells possess a voltage-gated proton current (IH) primarily carried by protons. This current, influenced by pH and calcium, may help muscle cells expel protons during action potentials.
Area of Science:
- Physiology
- Molecular Biology
- Biophysics
Background:
- Voltage-gated ion channels are crucial for cellular electrical activity.
- Proton currents play roles in various cellular processes, but their function in human muscle is less understood.
Purpose of the Study:
- To characterize the voltage-gated proton current (IH) in human myotubes.
- To determine the charge carrier and functional properties of IH in muscle cells.
Main Methods:
- Whole-cell patch-clamp technique applied to human muscle biopsies.
- Extracellular solution manipulations to identify charge carriers.
- Voltage-clamp analysis to assess activation, inactivation, and blocking properties.
Main Results:
- Identified a novel voltage-gated proton current (IH) in human myotubes.
- Protons (H+) were confirmed as the primary charge carriers of IH.
- IH activation is voltage-dependent, sensitive to extracellular pH, and blocked by extracellular divalent cations like Ca2+ in a voltage-dependent manner.
Conclusions:
- Human myotubes exhibit a unique voltage-gated proton current (IH).
- The properties of IH suggest a role in regulating intracellular pH during muscle activity.
- IH may contribute to proton extrusion from muscle cells, particularly during action potentials.