title: Effect of class III antiarrhythmic preparation nibentan on extrasystolic and post-extrasystolic contraction of rat papillary muscle.
abstract: The effect of nibentan (2.5 and 25 muM) on extrasystolic and post-extrasystolic contraction of isolated and perfused papillary muscle was studied. The muscle contracted in an isometric regimen at a rate of external electrical stimulation of 0.5 Hz in a temperature-stabilized chamber (36.0+0.5 degrees C). The extrasystolic contraction was induced with an extra electrical pulse applied 0.25 sec after the regular stimulus. Nibentan decreased the amplitude of extrasystolic contraction in a dose-dependent manner. At the same time, the effect of nibentan on extrasystolic contraction practically did not depend on its concentration. It is concluded that nibentan produces a dose-dependent effect on excitability of rat ventricular myocardium, and in parallel improves calcium-accumulating capacity of the sarcoplasmic reticulum in cardiomyocytes.
authors.affiliation: Research Institute of Cardiology, Tomsk Research Center, Siberian Division of the Russian Academy of Medical Sciences.
authors.forename: S A
authors.initials: SA
authors.lastname: Afanas'ev
authors.forename: I A
authors.initials: IA
authors.lastname: Lukavskaya
authors.forename: D S
authors.initials: DS
authors.lastname: Ugdyzhekova
authors.forename: S V
authors.initials: SV
authors.lastname: Popov
authors.forename: I V
authors.initials: IV
authors.lastname: Antonchenko
authors.forename: G O
authors.initials: GO
authors.lastname: Abubakirova
authors.forename: M A
authors.initials: MA
authors.lastname: Medvedev
mesh_terms: D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D001549:Benzamides / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004594:Electrophysiology; D006352:Heart Ventricles / Q000378:metabolism; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D010210:Papillary Muscles / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D012519:Sarcoplasmic Reticulum / Q000378:metabolism; D013599:Systole; D013696:Temperature
chemical_list: D000889:Anti-Arrhythmia Agents; D001549:Benzamides; C105049:nibentan; D002118:Calcium