Age-Related Changes in Electrophysiological Properties of Canine Purkinje Fibers: Effect of Ouabain

Abstract
Transmembrane potentials were recorded in Purkinje fibers obtained from dogs aged 1 day, 1 week, 2 weeks, 4 weeks and more than 1 year. After the initial impalements there was a time-dependent increase in diastolic potential. This hyperpolarization was more pronounced in the younger Purkinje fibers. Maximum diastolic potentials from 1-day-old puppies (-78.0 ± 1.2 mV), after 10 min of continuous impalement, were significantly less negative than those for adults (-84.2 ± 1.9 mV). Fibers from neonates exposed to ouabain do not depolarize as much as fibers from adults.