Cardiac actions in the dog of a new antagonist of adrenergic excitation which does not produce competitive blockade of adrenoceptors.
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TLDR
It is concluded that the cardiac actions of amiodarone are not produced by competitive blockade of β‐adrenoceptors.Abstract:
1. The cardiac actions of amiodarone, a benzofuran derivative used in the treatment of angina pectoris, have been compared with those of (±)-propranolol in anaesthetized dogs.
2. After three successive intravenous injections of propranolol, 0·5 mg/kg, had reduced the heart rate by 25%, a fourth dose had no further negative chronotropic action, but amiodarone, 10 mg/kg intravenously, at this point reduced the heart rate by 23%.
3. Amiodarone, 10 mg/kg intravenously, reduced, but did not abolish, cardiac responses to isoprenaline, 2 μg/kg intravenously. Subsequent successive injections of 10 mg/kg of amiodarone did not further block the responses to isoprenaline, but propranolol, 1 mg/kg intravenously, abolished them.
4. Amiodarone reduced cardiac chronotropic and inotropic responses to glucagon, which were not affected by propranolol.
5. Cardiac output was increased 5 min after amiodarone, 10 mg/kg intravenously, but at 10 min and thereafter it did not differ from control values. Propranolol, 1 mg/kg intravenously, reduced cardiac output by 17% at 5 min, and by 30% after 30 min.
6. From this and other evidence which is discussed, it is concluded that the cardiac actions of amiodarone are not produced by competitive blockade of β-adrenoceptors.read more
Citations
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In Vivo and In Vitro Antiarrhythmic Effects of SSR149744C in Animal Models of Atrial Fibrillation and Ventricular Arrhythmias
Patrick Gautier,Martine Serre,Sylvie Cosnier-Pucheu,Laurent Djandjighian,Alain Roccon,Jean-Marc Herbert,Dino Nisato +6 more
TL;DR: The present results show that SSR149744C is an effective antiarrhythmic agent in atrial fibrillation and in ventricular arrhythmias and like amiodarone and dronedarone, its efficiency in these animal models of arrh rhythmias is likely be related to its multifactorial mechanism of action.
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Effects of amiodarone on refractory myocardial infarction: Experimental study
Maria Anastasiou-Nana,John N. Nanas,Serafim Nanas,Ageliki C Rapti,Anastasios Poyadjis,Stamatina N. Stathaki,Spyridon D. Moulopoulos +6 more
TL;DR: In an experimental model of acute ischemia, intravenous amiodarone (10 mg/kg) influences positively the response to defibrillation of ventricular fibrillation refractory to lidocaine and epinephrine plus direct current countershocks.
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Antiadrenergic effect of chronic amiodarone therapy in human heart failure
TL;DR: Data indicate that amiodarone may exert beneficial effects on the failing human heart through a sympatholytic process, and this action appears to be relatively cardioselective.
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β-Blockers for the treatment of cardiac arrest from ventricular fibrillation?
TL;DR: To evaluate whether beta-blocker administration during the resuscitation of cardiac arrest from VF or pulseless ventricular tachycardia (VT) improves outcome, the MEDLINE and EMBASE databases were searched for human clinical trials, animal experimental trials, review articles, case reports and abstracts published between 1966 and September 2006.
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Refractory vasodilation after cardiopulmonary bypass for heart transplantation in recipients on combined amiodarone and angiotensin-converting enzyme inhibitor therapy : A role for vasopressin administration
TL;DR: The data suggest that in the face of an added insult, such as hemorrhage or anesthesia, blockade of only one or two of the components of this neurohormonai triad may lead to severe hemodynamic compromise during cardiac surgery.
References
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A study of the adrenotropic receptors
TL;DR: Experiments described in this paper indicate that although there are two kinds of adrenotropic receptors they cannot be classified simply as excitatory or inhibitory since each kind of receptor may have either action depending upon where it is found.
Journal ArticleDOI
The effect of amiodarone, a new anti‐anginal drug, on cardiac muscle
TL;DR: It was concluded that amiodarone had effects on cardiac action potentials similar to those which occur after thyroidectomy.
Journal ArticleDOI
Glucagon Its Enhancement of Cardiac Performance in the Cat and Dog and Persistence of its Inotropic Action Despite Beta-Receptor Blockade with Propranolol
TL;DR: In the dog, myocardial performance was markedly augmented by the administration of glucagon, 50 μg/kg iv, as indicated by an average increase of 72.2±18.8% in force recorded by a strain gauge arch, despite an average decrease of 3.8±1.2 cm H2O (P < 0.02) in left ventricular end-diastolic pressure.
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Cardiac Actions of Glucagon
TL;DR: The results of these studies are discussed in reference to the known metabolic actions of glucagon and the catecholamines and the possibility that they both share a common mechanism of action mediated through an increase in the intracellular concentration of cyclic 3′,5′ AMP.