title: ATP-sensitive K(+)-channel run-down is Mg2+ dependent.
abstract: 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.
authors.affiliation: Department of Pharmacology, University of Cambridge, U.K.
authors.forename: R Z
authors.initials: RZ
authors.lastname: Kozlowski
authors.forename: M L
authors.initials: ML
authors.lastname: Ashford
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D002460:Cell Line; D004533:Egtazic Acid / Q000494:pharmacology; D004553:Electric Conductivity; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology*; D008345:Manganese / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*; D051381:Rats
chemical_list: D015221:Potassium Channels; D008345:Manganese; D004533:Egtazic Acid; D000255:Adenosine Triphosphate; D008274:Magnesium