title: Specific up-regulation of mitochondrial F0F1-ATPase activity after short episodes of atrial fibrillation in sheep.
abstract: BACKGROUND
  Ventricular fibrillation induced by either digitalis intoxication or electrical stimulation is reported to alter myocardial energy by impairing the sarcolemmal Na,K-ATPase or the receptor for digitalis and the mitochondrial ATPase synthase or F0F1-ATPase. However, little is known about these membrane functions during atrial fibrillation (AF).
  
  
  RESULTS
  We analyzed the effects of electrically induced AF on biochemical activities of atrial F0F1-ATPase and Na,K-ATPase in sheep. A group of six sheep was subjected to direct short electrical stimulation of the right atrium to induce AF. Sham-operated sheep served as a control group. Microsomal and mitochondrial membranes of atrial muscle were isolated and tested for enzymatic activity. All paced sheep developed multiple episodes of sustained AF, with a mean total duration of 110 minutes over a 2-hour period. Data showed that short-term pacing-induced AF significantly activated membrane F0F1-ATPase activity (P < 0.05) without changes in cytochrome-c oxidase activity, Na,K-ATPase activity, ouabain sensitivity, and alpha1-subunit expression.
  
  
  CONCLUSIONS
  Specific activation of F0F1-ATPase activity is an early molecular consequence of sustained AF in sheep.
authors.affiliation: Laboratoire de Recherche Cardiologique, University of Marseille, School of Medicine, Centre Hospitalo-Universitaire Nord, France.
authors.forename: O
authors.initials: O
authors.lastname: Barbey
authors.forename: S
authors.initials: S
authors.lastname: Pierre
authors.forename: M J
authors.initials: MJ
authors.lastname: Duran
authors.forename: S
authors.initials: S
authors.lastname: Sennoune
authors.forename: S
authors.initials: S
authors.lastname: Lévy
authors.forename: J M
authors.initials: JM
authors.lastname: Maixent
mesh_terms: D000818:Animals; D001281:Atrial Fibrillation / Q000201:enzymology* / Q000209:etiology; D015415:Biomarkers; D015153:Blotting, Western; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D004558:Electric Stimulation / Q000009:adverse effects; D003576:Electron Transport Complex IV / Q000037:antagonists & inhibitors / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004791:Enzyme Inhibitors; D006325:Heart Atria / Q000201:enzymology*; D008861:Microsomes / Q000187:drug effects / Q000201:enzymology; D008929:Mitochondria, Heart / Q000187:drug effects / Q000201:enzymology*; D010042:Ouabain; D006180:Proton-Translocating ATPases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012756:Sheep; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D015415:Biomarkers; D004791:Enzyme Inhibitors; D010042:Ouabain; D003576:Electron Transport Complex IV; D006180:Proton-Translocating ATPases; D000254:Sodium-Potassium-Exchanging ATPase