title: Influence of ATP-dependent K(+)-channel opener on K(+)-cycle and oxygen consumption in rat liver mitochondria.
abstract: The influence of the K+(ATP)-channel opener diazoxide on the K+ cycle and oxygen consumption has been studied in rat liver mitochondria. It was found that diazoxide activates the K+(ATP)-channel in the range of nanomolar concentrations (50-300 nM, K(1/2) ~ 140 nM), which results in activation of K+/H+ exchange in mitochondria. The latter, in turn, accelerates mitochondrial respiration in respiratory state 2. The contribution of K+(ATP)-channel to the mitochondrial potassium cycle was estimated using the selective K+(ATP)-channel blocker glibenclamide. The data show that the relative contribution of K+(ATP)-channel in the potassium cycle of mitochondria is variable and increases only with the decrease in the ATP-independent component of K+ uptake. Possible mechanisms underlying the observed phenomena are discussed. The experimental results more fully elucidate the role of K+(ATP)-channel in the regulation of mitochondrial functions, especially under pathological conditions accompanied by impairment of the mitochondrial energy state.
authors.affiliation: Bogomolets Institute of Physiology, National Academy of Sciences of Ukraine, Kiev, 01601, Ukraine. a-dubensky@mail.ru
authors.forename: O V
authors.initials: OV
authors.lastname: Akopova
authors.forename: V I
authors.initials: VI
authors.lastname: Nosar
authors.forename: V A
authors.initials: VA
authors.lastname: Bouryi
authors.forename: I N
authors.initials: IN
authors.lastname: Mankovskaya
authors.forename: V F
authors.initials: VF
authors.lastname: Sagach
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D003981:Diazoxide / Q000494:pharmacology; D005905:Glyburide / Q000494:pharmacology; D054086:KATP Channels / Q000378:metabolism*; D008930:Mitochondria, Liver / Q000378:metabolism*; D010101:Oxygen Consumption; D011188:Potassium / Q000378:metabolism*; D026902:Potassium Channel Blockers / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar
chemical_list: D054086:KATP Channels; D026902:Potassium Channel Blockers; D000255:Adenosine Triphosphate; D003981:Diazoxide; D011188:Potassium; D005905:Glyburide