Cardiac effects of 16-acetyl-gitoxin, the active glycoside after penta-acetyl-gitoxin administration.
The inotropic and arrhythmogenic effects of 16-acetyl-gitoxin and digoxin were studied in isolated cardiac preparations and in anaesthetized dogs. ECG alteration-producing and lethal doses of both glycosides were determined in anaesthetized cats. In the isolated guinea-pig atrium, the properties of 16-acetyl-gitoxin are identical with those of ouabain, and in the isolated guinea-pig heart they are equal to those of digoxin, while gitoxin and penta-acetyl-gitoxin produce equieffective reactions at higher glycoside concentrations. In the cat, 75% of lethal doses of 16-acetyl-gitoxin and digoxin provoke ECG changes (qrs complex prolongation). The ratio of the lethal doses amounts to 1:2.8 and 1:3.5 (digoxin:16-acetyl-gitoxin). In case of equal contractile increment, the ratio of glycoside doses in dogs amounts to 1:1.3, while the percentages of rhythm disturbances following both glycosides are identical. Apart from slight deviations of the doses used, the cardiac properties of 16-acetyl-gitoxin are equal to those of digoxin.
D000113:Acetyldigoxins / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000503:physiopathology; D016275:Atrial Function; D002415:Cats; D004077:Digoxin / Q000031:analogs & derivatives*; D004285:Dogs; D005260:Female; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects / Q000502:physiology*; D006339:Heart Rate / Q000187:drug effects; D007536:Isomerism; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects*; D010042:Ouabain / Q000494:pharmacology; D013045:Species Specificity; D013329:Structure-Activity Relationship
D000113:Acetyldigoxins; D010042:Ouabain; D004077:Digoxin