title: Functioning of the mitochondrial ATP-dependent potassium channel in rats varying in their resistance to hypoxia. Involvement of the channel in the process of animal's adaptation to hypoxia.
abstract: The mechanism of tissue protection from ischemic damage by activation of the mitochondrial ATP-dependent K(+) channel (mitoK(ATP)) remains unexplored. In this work, we have measured, using various approaches, the ATP-dependent mitochondrial K(+) transport in rats that differed in their resistance to hypoxia. The transport was found to be faster in the hypoxia-resistant rats as compared to that in the hypoxia-sensitive animals. Adaptation of animals to the intermittent normobaric hypoxia increased the rate of transport. At the same time, the intramitochondrial concentration of K(+) in the hypoxia-sensitive rats was higher than that in the resistant and adapted animals. This indicates that adaptation to hypoxia stimulates not only the influx of potassium into mitochondria, but also K(+)/H(+) exchange. When mitoK(ATP) was blocked, the rate of the mitochondrial H(2)O(2) production was found to be significantly higher in the hypoxia-resistant rats than that in the hypoxia-sensitive animals. The natural flavonoid-containing adaptogen Extralife, which has an evident antihypoxic effect, increased the rate of the mitochondrial ATP-dependent K(+) transport in vitro and increased the in vivo tolerance of hypoxia-sensitive rats to acute hypoxia 5-fold. The involvement of the mitochondrial K(+) transport in the mechanism of cell adaptation to hypoxia is discussed.
authors.affiliation: Institute of Theoretical and Experimental Biophysics RAS, Pushchino, Moscow Region, 142290, Russia. mironova40@mail.ru
authors.forename: Galina D
authors.initials: GD
authors.lastname: Mironova
authors.forename: Maria I
authors.initials: MI
authors.lastname: Shigaeva
authors.forename: Elena N
authors.initials: EN
authors.lastname: Gritsenko
authors.forename: Svetlana V
authors.initials: SV
authors.lastname: Murzaeva
authors.forename: Olga S
authors.initials: OS
authors.lastname: Gorbacheva
authors.forename: Elena L
authors.initials: EL
authors.lastname: Germanova
authors.forename: Ludmila D
authors.initials: LD
authors.lastname: Lukyanova
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000378:metabolism; D000860:Hypoxia / Q000378:metabolism*; D008297:Male; D010936:Plant Extracts / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism*; D015221:Potassium Channels / Q000378:metabolism*; D011312:Pressure; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
chemical_list: D010936:Plant Extracts; D015221:Potassium Channels; C527119:extralife; C117780:mitochondrial K(ATP) channel; D006861:Hydrogen Peroxide; D011188:Potassium