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Specific Up‐Regulation of Mitochondrial F 0 F 1 ‐ATPase Activity after Short Episodes of Atrial Fibrillation in Sheep
Author(s) -
BARBEY ODILE,
PIERRE SANDRINE,
DURAN MARIEJOSÉE,
SENNOUNE SOUAD,
LÉVY SAMUEL,
MAIXENT JEANMICHEL
Publication year - 2000
Publication title -
journal of cardiovascular electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.193
H-Index - 138
eISSN - 1540-8167
pISSN - 1045-3873
DOI - 10.1111/j.1540-8167.2000.tb00339.x
Subject(s) - atrial fibrillation , medicine , stimulation , atpase , ouabain , digitalis , cytochrome c oxidase , endocrinology , cardiology , mitochondrion , enzyme , chemistry , biochemistry , sodium , heart failure , organic chemistry
ATPase Activity and Atrial Fibrillation. Introduction : 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 F 0 ,F 1 ‐ATPase. However, little is known about these membrane functions during atrial fibrillation (AF). Methods and Results : We analyzed the effects of electrically induced AF on biochemical activities of atrial F 0 F 1 ‐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 F 0 F 1 ‐ATPase activity (P < 0.05) without changes in cytochrome‐c oxidase activity, Na,K‐ATPase activity, ouabain sensitivity, and α 1 ‐subunit expression. Conclusion : Specific activation of F 0 F 1 ‐ATPase activity is an early molecular consequence of sustained AF in sheep.