Ionic mechanisms underlying the effects of Vasoactive intestinal polypeptide on canine atrial myocardium

Yutao Xi, Geru Wu, Tomohiko Ai, Nancy Cheng, Jurij Matija Kalisnik, Junping Sun, Shahrzad Abbasi, Donghui Yang, Christopher Fan, Xiaojing Yuan, Suwei Wang, Macarthur Elayda, Igor D. Gregoric, Bharat K. Kantharia, Shien Fong Lin, Jie Cheng

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

Background: Vasoactive intestinal polypeptide (VIP) is released from intracardiac neurons during vagal stimulation, ischemia, and heart failure, which are associated with increased vulnerability to atrial fibrillation. VIP shortens atrial effective refractory periods in dogs. Endogenous VIP contributes to vagally mediated acceleration of atrial electric remodeling. VIP is also shown to prolong the duration of acetylcholine-induced atrial fibrillation. However, the ionic mechanisms underlying VIP effects are largely unknown. Methods and Results: The effects of VIP 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 effects of VIP on action potential durations (APDs) in isolated canine left atria. VIP shortened APD and slowed conduction velocity in a dosedependent manner. Furthermore, VIP increased spatial heterogeneity of APD and conduction velocity, as assessed by the SDs of APD and conduction velocity, and atrial fibrillation inducibility. Conclusions: Through 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.

Original languageEnglish (US)
Pages (from-to)976-983
Number of pages8
JournalCirculation: Arrhythmia and Electrophysiology
Volume6
Issue number5
DOIs
StatePublished - Oct 1 2013
Externally publishedYes

Keywords

  • Action potentials
  • Atrial fibrillation
  • Ion channels
  • Vasoactive intestinal polypeptide

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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