title: 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.
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000367:Age Factors; D000818:Animals; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D005260:Female; D006329:Heart Conduction System / Q000502:physiology*; D008297:Male; D010042:Ouabain / Q000494:pharmacology*; D011188:Potassium / Q000378:metabolism; D011690:Purkinje Fibers / Q000187:drug effects / Q000502:physiology*
chemical_list: D010042:Ouabain; D011188:Potassium