O. Barbey et al., Specific up-regulation of mitochondrial F0F1-ATPase activity after short episodes of atrial fibrillation in sheep, J CARD ELEC, 11(4), 2000, pp. 432-438
Citations number
63
Categorie Soggetti
Cardiovascular & Respiratory Systems","Cardiovascular & Hematology Research
ATPase Activity and Atrial Fibrillation. Introduction: Ventricular fibrilla
tion induced by either digitalis intoxication or electrical stimulation is
reported to alter myocardial energy by impairing the sarcolemmal Na,K-ATPas
e or the receptor for digitalis and the mitochondrial ATPase synthase or F0
F1-ATPase. However, little is known about these membrane functions during a
trial fibrillation (AF).
Methods and Results: We analyzed the effects of electrically induced AF on
biochemical activities of atrial F0F1-ATPase and Na,K-ATPase in sheep. A gr
oup of six sheep was subjected to direct short electrical stimulation of th
e 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 pe
riod. Data showed that short-term pacing-induced AF significantly activated
membrane F0F1-ATPase artivity (P < 0.05) without changes in cytochrome-c o
xidase activity, Na,K-TPase activity, ouabain sensitivity, and alpha(1)-sub
unit expression,
Conclusion: Specific activation of F0F1-ATPase activity is an early molecul
ar consequence of sustained AF in sheep.