Spironolactone diminishes spontaneous ventricular premature beats by reducing HCN4 protein expression in rats with

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Isolation of Atrial Cardiomyocytes from a Rat Model of Metabolic Syndrome-related Heart Failure with Preserved Ejection Fraction
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Isolation of Atrial Cardiomyocytes from a Rat Model of Metabolic Syndrome-related Heart Failure with Preserved Ejection Fraction

Published on: July 26, 2018

Tao Song1, Jing Yang, Yuan Yao

  • 1Department of Cardiology, Renmin Hospital of Wuhan University, and Cardiovascular Research Institute,Wuhan University, Wuhan 430060, PR China.

Molecular Medicine Reports
|April 7, 2011
PubMed

Insights

Spironolactone treatment reduced ventricular premature beats in a rat myocardial infarction model. This effect was linked to a decrease in HCN4 protein expression, suggesting a new therapeutic avenue for post-MI arrhythmias.

Area of Science:

  • Cardiology
  • Molecular Biology
  • Pharmacology

Background:

  • Hyperpolarization-activated current (If), mediated by hyperpolarization-activated and cyclic nucleotide-gated (HCN) channels, is crucial for cardiac pacemaker cells.
  • HCN channels may contribute to arrhythmias in working myocardium under pathological conditions like myocardial infarction (MI).
  • Spironolactone, an aldosterone blocker, has shown potential in preventing spontaneous ventricular arrhythmias post-MI.

Purpose of the Study:

  • To investigate the effect of spironolactone on HCN channel expression and ventricular premature beats (VPBs) in a rat MI model.
  • To elucidate the potential mechanism by which spironolactone exerts its anti-arrhythmic effects.

Main Methods:

  • A rat model of myocardial infarction was established by ligating the left coronary artery.
  • Rats were treated with saline or spironolactone (80 µg/kg/day) for 7 days post-MI.
  • HCN2 and HCN4 protein levels were assessed, and VPBs were quantified. The effect of an If current inhibitor (ivabradine) was also evaluated.

Main Results:

  • MI induced an increase in HCN2 and HCN4 protein levels and a significant rise in VPBs compared to sham-operated rats.
  • Spironolactone treatment prevented the MI-induced increase in HCN4 protein levels and reduced the occurrence of VPBs.
  • Inhibition of If current with ivabradine further reduced VPBs in both control and spironolactone-treated groups to similar levels.

Conclusions:

  • Spironolactone may prevent ischemia-induced VPBs by reducing HCN4 protein expression towards basal levels.
  • These findings suggest a potential therapeutic role for spironolactone in managing ventricular arrhythmias following myocardial infarction.

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