Effects of alpha-adrenoceptor agonists and antagonists on ouabain-induced arrhythmias and cardiac arrest in guinea-pig.
Effects of alpha-adrenoceptor agonists and antagonists with different affinity for alpha 1- and alpha 2-receptors on ouabain-induced arrhythmias in guinea-pigs were studied. Early arrhythmias, ventricular fibrillation and cardiac arrest were induced in anaesthetized guinea-pigs by the slow intravenous infusion of ouabain. Phenylephrine and yohimbine potentiated the cardiotoxicity of ouabain significantly whereas prazosin and clonidine showed significant antiarrhythmic effects and delayed the cardiac arrest. It is concluded that selective alpha 1-receptor stimulation and alpha 2-receptor blockade increases the cardiotoxic effects of ouabain and selective alpha 2-receptor stimulation and alpha 1-receptor blockade inhibits ouabain-induced arrhythmias and cardiac arrest in guinea-pigs.
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000818:Animals; D000889:Anti-Arrhythmia Agents; D001145:Arrhythmias, Cardiac / Q000139:chemically induced*; D001794:Blood Pressure / Q000187:drug effects; D004347:Drug Interactions; D005260:Female; D006168:Guinea Pigs; D006323:Heart Arrest / Q000139:chemically induced*; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D010042:Ouabain / Q000633:toxicity
D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D000889:Anti-Arrhythmia Agents; D010042:Ouabain