Cuprous ions activate glibenclamide-sensitive potassium channel in liver mitochondria.
Cuprous ions at micromolar concentrations induced swelling of rat liver mitochondria in isotonic solutions of potassium thiocyanate and potassium acetate. The swelling in K-acetate in the presence of the protonophore [corrected] carbonyl cyanide m-chloropenylhydrazone was partly inhibited by glibenclamide. In K(+)-containing media, Cu+ collapsed the mitochondrial membrane potential formed by operation of the respiratory chain with succinate or tetramethyl p-phenylenediamine + ascorbate as substrates or by the proton-pumping ATPase. In contrast, in K(+)-free media, isotonic sucrose or choline chloride, but not in NaC1, Cu+ induced a transient potassium gradient potential. These results indicate that cuprous ions at low concentrations, apart from promoting the electroneutral K+/H+ exchange, facilitate the uniport of K+, presumably by activating the mitochondrial potassium channel sensitive to glibenclamide.
Wojtczak
L
L
Nencki Institute of Experimental Biology, Warsaw, Poland. LWAC@nencki.gov.pl
Nikitina
E R
ER
Czyz
A
A
Skulskii
I A
IA
D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D003300:Copper / Q000494:pharmacology*; D019327:Copper Sulfate; D004058:Diffusion; D005905:Glyburide / Q000494:pharmacology*; D007425:Intracellular Membranes / Q000187:drug effects / Q000502:physiology; D007700:Kinetics; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D008930:Mitochondria, Liver / Q000187:drug effects / Q000502:physiology*; D008933:Mitochondrial Swelling / Q000187:drug effects*; D009840:Oligomycins / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D012402:Rotenone / Q000494:pharmacology; D014634:Valinomycin / Q000494:pharmacology
D009840:Oligomycins; D015221:Potassium Channels; D012402:Rotenone; D014634:Valinomycin; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D003300:Copper; D019327:Copper Sulfate; D001205:Ascorbic Acid; D011188:Potassium; D005905:Glyburide