title: ATP-sensitive K+ channels in renal mitochondria.
abstract: Isolated kidney mitochondria swell when incubated in hyposmotic solutions containing K+ salts in a manner inhibited by ATP, ADP, 5-hydroxydecanoate, and glibenclamide and stimulated by GTP and diazoxide. These results suggest the existence of ATP-sensitive K+ channels in these mitochondria, similar to those previously described in heart, liver, and brain. Renal mitochondrial ATP-sensitive K+ uptake rates are approximately 140 nmol.min-1.mg protein-1. This K+ transport results in a slight increase in respiration and decrease in the inner membrane potential. In addition, the activation of ATP-inhibited K+ uptake using diazoxide leads to a decrease of ATP hydrolysis through the reverse activity of the F0F1 ATP synthase when respiration is inhibited. In conclusion, we characterize an ATP-sensitive K+ transport pathway in kidney mitochondria that affects volume, respiration, and membrane potential and may have a role in the prevention of mitochondrial ATP hydrolysis.
authors.affiliation: Departamento de Fisiologia e Biofísica, Instituto de Ciências Biomédicas, Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes 748, Cidade Universitária, 05508-900 São Paulo, Brazil.
authors.forename: Douglas V
authors.initials: DV
authors.lastname: Cancherini
authors.forename: Leonardo G
authors.initials: LG
authors.lastname: Trabuco
authors.forename: Nancy A
authors.initials: NA
authors.lastname: Rebouças
authors.forename: Alicia J
authors.initials: AJ
authors.lastname: Kowaltowski
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D001692:Biological Transport / Q000187:drug effects / Q000502:physiology; D019069:Cell Respiration / Q000502:physiology; D019194:Ischemic Preconditioning; D007668:Kidney / Q000378:metabolism*; D008297:Male; D008564:Membrane Potentials / Q000502:physiology; D008928:Mitochondria / Q000378:metabolism*; D008933:Mitochondrial Swelling / Q000187:drug effects / Q000502:physiology; D011188:Potassium / Q000378:metabolism; D015221:Potassium Channels / Q000378:metabolism*; D006180:Proton-Translocating ATPases / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
chemical_list: D015221:Potassium Channels; D000255:Adenosine Triphosphate; D006180:Proton-Translocating ATPases; D011188:Potassium