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  • Ionic mechanisms underlying the effects of vasoactive intestinal polypeptide on canine atrial myocardium
    Xi, Yutao ...
    BackgroundVasoactive intestinal polypeptide (VIP) is released from intracardiac neurons during vagal stimulation, ischemia and heart failure which are associated with increased vulnerability to ... atrial fibrillation (AF). VIP shortens atrial effective refractory periods in dogs. Endogenous VIP contributes to vagally mediated acceleration of atrial electrical remodeling. VIP is also shown to prolong the duration of acetylcholine-induced AF. However, the ionic mechanisms underlying VIP effects are largely unknown. Methods and ResultsVIP's effects on transmembrane ion channels were studied in canine atrial cardiomyocytes using patch-clamp techniques. VIP increased delayed rectifier K+ current and L-type calcium current but decreased the transient outward K+ current and sodium current. Optical mapping technique was used to assess VIP's effects on action potential durations (APD) in isolated canine left atria. VIP shortened APD and slowed conduction velocity (CV) in a dose-dependent manner. Furthermore, VIP increased spatial heterogeneity of APD and CV, as assessed by the standard deviations of APD and CV, and AF inducibility. ConclusionsThrough its diverse effects on ion channels, VIP shortens APD with increased APD spatial heterogeneity and decreases intra-atrial conduction velocity, which may play an important role in the pathogenesis of atrial arrhythmias in scenarios where VIP release is increased.
    Source: Circulation. Arrhythmia and electrophysiology. - ISSN 1941-3149 (Vol. 6, iss. 5, Oct . 2013, str. 976-983)
    Type of material - article, component part ; adult, serious
    Publish date - 2013
    Language - english
    COBISS.SI-ID - 1125804

    Link(s):

    http://circep.ahajournals.org/content/early/2013/09/16/CIRCEP.113.000518
    DOI

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