Key result
Isoproterenol increased delayed rectifier potassium current in adult canine epicardial cells (from 10.23 to 13.43 pA/pF, P<0.05) but not in cells from dogs <30 days old.
Population
Canine ventricular epicardial slices and isolated epicardial myocytes from adult dogs and dogs < 30 days old
Comparison
Isoproterenol (10^-7 M and 10^-5 M) vs Control (baseline without isoproterenol)
Design
Preclinical
Authors
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Does not support extrapolation to pediatric patients; leaves open whether IK maturation influences human repolarization.
Absolute Event Rate: 13.43% vs 10.23%
p-value: p=<0.05
Beta-adrenergic regulation of repolarization in canine epicardium undergoes developmental changes, primarily controlled at the level of the IK channel rather than the beta-adrenergic receptor cascade.
Charpentier et al. (1996) studied this question. Isoproterenol vs. Control (baseline) was evaluated on Delayed rectifier potassium current (IK) in adult cells (pA/pF) (p=<0.05). Isoproterenol increased delayed rectifier potassium current in adult canine epicardial cells (from 10.23 to 13.43 pA/pF, P<0.05) but not in cells from dogs <30 days old.
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