Absence of Rgs5 prolongs cardiac repolarization and predisposes to ventricular tachyarrhythmia in mice

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Ambulatory ECG Recording in Mice
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Ambulatory ECG Recording in Mice

Published on: May 27, 2010

Mu Qin1, He Huang, Teng Wang

  • 1Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, China.

Journal of Molecular and Cellular Cardiology
|October 20, 2012
PubMed

Insights

The absence of regulator of G-protein signaling 5 (Rgs5) in mice prolongs cardiac repolarization and increases ventricular arrhythmias. This is linked to reduced K+ currents and altered expression of specific potassium channel genes.

Area of Science:

  • Cardiovascular Physiology
  • Molecular Cardiology
  • Electrophysiology

Background:

  • Regulator of G-protein signaling 5 (Rgs5) is a negative regulator of G-protein signaling.
  • Cardiac repolarization and arrhythmia are critical determinants of heart function and disease.

Purpose of the Study:

  • To investigate the role of Rgs5 in cardiac repolarization and arrhythmia susceptibility in mice.
  • To elucidate the electrophysiological and molecular mechanisms underlying Rgs5 deficiency-induced cardiac abnormalities.

Main Methods:

  • Utilized wild-type and Rgs5 knockout (Rgs5(-/-)) mouse models.
  • Performed in vivo, in vitro, and cellular electrophysiological assessments.
  • Analyzed K+ currents and expression of voltage-dependent potassium channels (Kv channels) in ventricular myocytes.

Main Results:

  • Rgs5(-/-) mice exhibited significantly prolonged QT interval and action potential duration (APD).
  • Reduced outward voltage-dependent K+ currents (I(peak), I(to), I(Kur), I(ss)) were observed in Rgs5(-/-) ventricular myocytes.
  • Downregulation of Kv4.2, Kv4.3, Kv1.5, and Kv2.1 gene and protein expression was found in Rgs5(-/-) ventricles.
  • Rgs5 deficiency facilitated electrically induced ventricular tachyarrhythmias, associated with increased APD dispersion and spatial heterogeneity of K+ currents.

Conclusions:

  • Absence of Rgs5 leads to cardiac electrophysiological abnormalities, including prolonged repolarization and ventricular tachyarrhythmia.
  • Remodeling of voltage-dependent K+ currents and altered Kv channel expression are key mechanisms involved.
  • Rgs5 plays a significant role in maintaining normal cardiac electrical function.

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