Abstract
Mitochondrial ATP-regulated potassium (mitoKATP) channels play an important role in cardioprotection. Single channel activity was measured after reconstitution of inner mitochondrial membranes from bovine myocardium into a planar lipid bilayer. After incorporation, the potassium channel was recorded with a mean conductance of 103+/-9 pS. The channel activity was inhibited by ATP/Mg and activated by GDP. Magnesium ions alone affected, in a dose dependent manner, both the channel conductance and the open probability. Magnesium ions regulated the mitoKATP channel only when added to the trans compartment. We conclude that Mg2+ regulates the cardiac mitoKATP channel from the matrix site by affecting both the channel conductance and gating.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adenosine Triphosphate / pharmacology
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Adenosine Triphosphate / physiology
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Animals
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Cations, Divalent / pharmacology
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Cattle
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Electric Conductivity
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Guanosine Diphosphate / pharmacology
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Guanosine Diphosphate / physiology
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Intracellular Membranes / drug effects
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Intracellular Membranes / physiology
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Magnesium / pharmacology
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Magnesium / physiology*
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Membrane Proteins / agonists
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Membrane Proteins / antagonists & inhibitors
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Membrane Proteins / metabolism*
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Mitochondria, Heart / metabolism*
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Mitochondria, Heart / physiology
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Potassium Channels
Substances
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Cations, Divalent
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Membrane Proteins
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Potassium Channels
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mitochondrial K(ATP) channel
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Guanosine Diphosphate
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Adenosine Triphosphate
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Magnesium