Increasing gap junction coupling suppresses ibutilide‑induced torsades de pointes

  • Authors:
    • Lei Ruan
    • Xiaoqing Quan
    • Liandong Li
    • Rong Bai
    • Mingke Ni
    • Rende Xu
    • Cuntai Zhang
  • View Affiliations

  • Published online on: March 4, 2014     https://doi.org/10.3892/etm.2014.1601
  • Pages: 1279-1284
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Abstract

Drug‑induced torsades de pointes (TdP) is common with class III antiarrhythmic drugs. Increased transmural dispersion of repolarization (TDR) contributes significantly to the development of TdP. Gap junctions play an important role in maintaining TDR in long QT syndrome. The present study examined the effect of a gap junction enhancer, antiarrhythmic peptide 10 (AAP10), on ibutilide‑induced TdP. Coronary‑perfused rabbit ventricular wedge preparations were used to evaluate the effect of AAP10 on ibutilide‑induced arrhythmia. Transmural electrocardiograms and action potentials were recorded simultaneously. Early afterdepolarizations (EADs), R‑on‑T extrasystole, TdP and changes in Tpeak‑end (Tp‑e) and the Tp‑e/QT ratio were observed. Changes in the levels of non‑phosphorylated connexin 43 (Cx43) were measured by immunoblotting. Compared with those in the control group, the QT interval, Tp‑e/QT and incidence rates of EAD and TdP increased with augmented dephosphorylation in the ventricular wedge preparations perfused with ibutilide under conditions of hypokalemia and hypomagnesemia. In the presence of AAP10, the incidence rates of EAD and TdP were reduced and the Tp‑e/QT ratio decreased, with a parallel reduction in the level of non‑phosphorylated Cx43. The results indicate that AAP10 suppressed ibutilide‑induced TdP under conditions of hypokalemia and hypomagnesemia by decreasing TDR. AAP10 reduced TDR, possibly by preventing the dephosphorylation of Cx43 and thereby increasing myocardial cell gap junction coupling.
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May-2014
Volume 7 Issue 5

Print ISSN: 1792-0981
Online ISSN:1792-1015

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Spandidos Publications style
Ruan L, Quan X, Li L, Bai R, Ni M, Xu R and Zhang C: Increasing gap junction coupling suppresses ibutilide‑induced torsades de pointes. Exp Ther Med 7: 1279-1284, 2014.
APA
Ruan, L., Quan, X., Li, L., Bai, R., Ni, M., Xu, R., & Zhang, C. (2014). Increasing gap junction coupling suppresses ibutilide‑induced torsades de pointes. Experimental and Therapeutic Medicine, 7, 1279-1284. https://doi.org/10.3892/etm.2014.1601
MLA
Ruan, L., Quan, X., Li, L., Bai, R., Ni, M., Xu, R., Zhang, C."Increasing gap junction coupling suppresses ibutilide‑induced torsades de pointes". Experimental and Therapeutic Medicine 7.5 (2014): 1279-1284.
Chicago
Ruan, L., Quan, X., Li, L., Bai, R., Ni, M., Xu, R., Zhang, C."Increasing gap junction coupling suppresses ibutilide‑induced torsades de pointes". Experimental and Therapeutic Medicine 7, no. 5 (2014): 1279-1284. https://doi.org/10.3892/etm.2014.1601