ATP-sensitive K(+)-channel run-down is Mg2+ dependent

Proc R Soc Lond B Biol Sci. 1990 Jun 22;240(1298):397-410. doi: 10.1098/rspb.1990.0044.


ATP-sensitive K(+)-channel currents were recorded from isolated membrane patches and voltage-clamped CRI-G1 insulin-secreting cells. Internal Mg2+ ions inhibited ATP-K+ channels by a voltage-dependent block of the channel current and decrease of open-state probability. The run-down of ATP-K+ channel activity was also shown to be [Mg2+]i dependent, being almost abolished in Mg2(+)-free conditions. Substitution of Mn2+ for Mg2+ did not prevent run-down, nor did the presence of phosphate-donating nucleotides, a protease or phosphatase inhibitor or replacement of Cl- by gluconate.

MeSH terms

  • Adenosine Triphosphate / pharmacology*
  • Animals
  • Cell Line
  • Egtazic Acid / pharmacology
  • Electric Conductivity
  • Kinetics
  • Magnesium / pharmacology*
  • Manganese / pharmacology
  • Membrane Potentials / drug effects
  • Potassium Channels / drug effects
  • Potassium Channels / physiology*
  • Rats


  • Potassium Channels
  • Manganese
  • Egtazic Acid
  • Adenosine Triphosphate
  • Magnesium