Amiodarone, adrenoceptor responsiveness and ischaemia- and reperfusion-induced arrhythmias.

Abstract

Experiments were performed in rats which had been pretreated with amiodarone 50 mg kg-1 day-1 p.o. for 4 weeks. In anaesthetized animals subject to 25 min of coronary artery occlusion, the rats which had received amiodarone had fewer ischaemia-induced ventricular premature beats than the controls (381 +/- 106 compared with 815 +/- 215, P = 0.070). The duration of arrhythmias induced by reperfusion following 5 min of ischaemia was also less in the rats which had received amiodarone than in the controls (43.8 +/- 6.8 and 16.0 +/- 3.1 s respectively). Pretreatment of rats with amiodarone reduced the maximum driving frequency of both isolated left atria and papillary muscles. There were no differences between the responses to alpha- or beta-adrenoceptor agonists or to calcium in papillary muscle preparations from amiodarone-pretreated and control rats. These results suggest that the antiarrhythmic activity of chronic amiodarone seen in the present study does not depend on changes in ventricular adrenoceptor responsiveness.

• Authors: S J Coker, R Chess-Williams
• Journal: European journal of pharmacology (Eur J Pharmacol) Vol. 201 Issue 1 Pg. 103-9 (Aug 16 1991) ISSN: 0014-2999 [Print] Netherlands
• PMID: 1665418 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Receptors, Adrenergic, beta
• Amiodarone

Topics

• Amiodarone (administration & dosage, pharmacology)
• Animals
• Arrhythmias, Cardiac (etiology, prevention & control)
• Coronary Disease (complications)
• In Vitro Techniques
• Male
• Myocardial Contraction (drug effects)
• Myocardial Reperfusion Injury (complications)
• Rats
• Rats, Inbred Strains
• Receptors, Adrenergic, beta (drug effects)