title: Effects of 4-aminopyridine on pacemaker activity of frog sinus venosus.
abstract: The effects of low concentrations of 4-aminopyridine (4-AP) were studied on the frog sinus venosus by means of intracellular microelectrodes. 4-AP depressed spontaneous automaticity. This effect was not reversed by atropine. 4-AP also prolonged the sinus action potential repolarization and slowed the rate of diastolic depolarization. These effects are attributed to blockade of potassium conductance.
mesh_terms: D000631:Aminopyridines / Q000494:pharmacology*; D000818:Animals; D001001:Anura; D001285:Atropine / Q000494:pharmacology; D006321:Heart / Q000502:physiology*; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects*; D011188:Potassium / Q000502:physiology; D012964:Sodium / Q000502:physiology; D013997:Time Factors
chemical_list: D000631:Aminopyridines; D001285:Atropine; D012964:Sodium; D011188:Potassium