title: Aminopyridine lengthened the plateau phase of action potentials in mouse sinoatrial node cells.
abstract: Duration of the plateau phase (phase 2) of action potentials in pacemaker cells in mouse sinoatrial node characterized by low upstroke rate during the rapid depolarization (dV/dt max <7 V/sec, phase 0) and in atrial-like cells with dV/dt max <100 V/sec were prolonged by 50% with 4-aminopyridine in concentrations of 0.7 and 0.1 mM, respectively. This blocker did not lengthen the terminal repolarization (phase 3). The above changes were accompanied by a 20-80% decrease in dV/dt max in comparison to the control. It is hypothesized that the short-term (transient) outward current Ito takes a part in the plateau formation and modulates the duration of the rapid depolarization phase of action potentials in mouse sinoatrial node cells.
authors: Komi Research Institute of Physiology, Ural Branch of the Russian Academy of Sciences, Syktyvkar, Russia. golovko@physiol.komisc.ru.
authors: M A
authors: MA
authors: Gonotkov
authors: V A
authors: VA
authors: Golovko
mesh_terms: D015761:4-Aminopyridine / Q000494:pharmacology*; D000200:Action Potentials / Q000187:drug effects*; D000818:Animals; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D009200:Myocardial Contraction / Q000187:drug effects; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000502:physiology; D026902:Potassium Channel Blockers / Q000494:pharmacology*; D012849:Sinoatrial Node / Q000166:cytology / Q000187:drug effects / Q000502:physiology*
chemical_list: D026902:Potassium Channel Blockers; D015761:4-Aminopyridine