Built for speed |
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Authors: | Andrew P Braun |
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Institution: | Faculty of Medicine; University of Calgary; Calgary, Alberta, Canada |
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Abstract: | Many of us were taught in high school biology that the action potential waveform in nerves and other excitable tissues was generated by an initial rapid influx of external Na+ ions across the plasma membrane, followed by an outward movement of intracellular K+ ions. The former event, mediated by voltage-gated Na+ channels, is responsible for the fast depolarizing upstroke of the action potential, while voltage-gated K+ channels are responsible for the subsequent repolarizing phase, which largely controls action potential duration. Although Hodgkin and Huxley described the fundamental importance of this sequential activation process more than 60 y ago, the molecular and structural details underlying the faster activation of voltage-gated Na+ (Nav) vs. K+ (Kv) channels have yet to be fully resolved. |
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Keywords: | voltage sensor domain gating current Nav channel Kv channel hydrophobicity |
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