title: Canine cardiac digitalis receptors are preserved in congestive heart failure induced by rapid ventricular pacing.
abstract: In dogs, it has been reported that acute ischemia or severe and terminal heart failure results in a selective reduction of myocardial alpha 3 isoform of Na, K-ATPase activity. The aim of this study was to evaluate if a similar change in the two canine digitalis receptor isoforms occurs following 4 weeks of rapid ventricular pacing-induced heart failure without profound necrosis. Heart failure was induced in dogs by rapid ventricular pacing (240 beats x min-1). Digitalis receptors were quantitated by [3H]-ouabain binding with isolated microsomal membranes from sham-operated (n = 3) and heart failure dogs (n = 4) and by Western blot analysis using specific alpha 1 and alpha 3 polyclonal antibodies. In kinetic studies, similar dissociation rates of 19 to 22 x 10(-4) s-1 and 1.3 to 2.4 x 10(-4) s-1 corresponding to high and low affinity sites respectively, were found in sham-operated and CHF dogs. Immunoblotting showed similar abundance of alpha 1 isoform in the two groups; however, levels of alpha 3 were increased by at least 50% in pacing-induced heart failure animals. In conclusion, heart failure selectively modulates the expression of cardiac alpha 3 isoform in dogs.
authors.affiliation: Cardiac Research Laboratories, School of Medicine, University Aix-Marseille, France.
authors.forename: O
authors.initials: O
authors.lastname: Barbey
authors.forename: A
authors.initials: A
authors.lastname: Gerbi
authors.forename: F
authors.initials: F
authors.lastname: Paganelli
authors.forename: K
authors.initials: K
authors.lastname: Robert
authors.forename: S
authors.initials: S
authors.lastname: Lévy
authors.forename: J M
authors.initials: JM
authors.lastname: Maixent
mesh_terms: D000818:Animals; D015153:Blotting, Western; D004285:Dogs; D006333:Heart Failure / Q000201:enzymology*; D006339:Heart Rate; D007700:Kinetics; D009206:Myocardium / Q000201:enzymology*; D010042:Ouabain / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
chemical_list: C027082:digitalis receptor; D010042:Ouabain; D000254:Sodium-Potassium-Exchanging ATPase