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Acute effects of amiodarone on sodium currents in isolated neonatal ventricular myocytes: comparison with procainamide.
- Source :
-
Developmental pharmacology and therapeutics [Dev Pharmacol Ther] 1992; Vol. 19 (2-3), pp. 118-30. - Publication Year :
- 1992
-
Abstract
- Recent studies suggest that amiodarone's acute clinical effects in infants and children are related predominantly to its class I antiarrhythmic activity. However, the effects of amiodarone on Na+ currents have not been investigated directly in immature cardiac cells. Accordingly, the tight seal whole cell voltage clamp technique was used to measure time- and voltage-dependent Na+ currents in acutely isolated neonatal ventricular myocytes from 2- to 5-day-old rabbits, before and after addition of amiodarone (0.1-10 microM). To evaluate the class I antiarrhythmic activity of amiodarone in this age group, the effects of amiodarone on Na+ currents were compared with those of procainamide. Similar to procainamide, amiodarone significantly decreased peak inward Na+ current in neonatal ventricular myocytes. Moreover, both amiodarone and procainamide shifted the steady-state inactivation curve to more negative membrane potentials and delayed recovery of the Na+ current from inactivation. Thus, the effects of amiodarone on the Na+ current in immature myocardium are qualitatively similar to those of procainamide, suggesting that amiodarone may act acutely as a class I antiarrhythmic agent in the newborn heart.
- Subjects :
- Animals
Animals, Newborn
Cells, Cultured
Heart Ventricles cytology
Heart Ventricles drug effects
Membrane Potentials drug effects
Myocardium cytology
Myocardium metabolism
Rabbits
Sodium metabolism
Sodium physiology
Sodium Channels physiology
Ventricular Function
Amiodarone pharmacology
Heart drug effects
Heart physiology
Procainamide pharmacology
Sodium Channels drug effects
Subjects
Details
- Language :
- English
- ISSN :
- 0379-8305
- Volume :
- 19
- Issue :
- 2-3
- Database :
- MEDLINE
- Journal :
- Developmental pharmacology and therapeutics
- Publication Type :
- Academic Journal
- Accession number :
- 1340433
- Full Text :
- https://doi.org/10.1159/000457473