Matrix Mg2+ regulates mitochondrial ATP-dependent potassium channel from heart.
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.
Bednarczyk
Piotr
P
Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, 3 Pasteur St., 02-093 Warsaw, Poland.
Dołowy
Krzysztof
K
Szewczyk
Adam
A
D000255:Adenosine Triphosphate / Q000494:pharmacology / Q000502:physiology; D000818:Animals; D002413:Cations, Divalent / Q000494:pharmacology; D002417:Cattle; D004553:Electric Conductivity; D006153:Guanosine Diphosphate / Q000494:pharmacology / Q000502:physiology; D007425:Intracellular Membranes / Q000187:drug effects / Q000502:physiology; D008274:Magnesium / Q000494:pharmacology / Q000502:physiology*; D008565:Membrane Proteins / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008929:Mitochondria, Heart / Q000378:metabolism* / Q000502:physiology; D015221:Potassium Channels
D002413:Cations, Divalent; D008565:Membrane Proteins; D015221:Potassium Channels; C117780:mitochondrial K(ATP) channel; D006153:Guanosine Diphosphate; D000255:Adenosine Triphosphate; D008274:Magnesium