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Assessment of Myofilament Ca2+ Sensitivity Underlying Cardiac Excitation-contraction Coupling
08:29

Assessment of Myofilament Ca2+ Sensitivity Underlying Cardiac Excitation-contraction Coupling

Published on: August 1, 2016

Peroxynitrite-induced cardiac depression: role of myofilament desensitization and cGMP pathway

Friedrich Brunner1, Gerald Wölkart

  • 1Institut für Pharmakologie und Toxikologie, Karl-Franzens-Universität Graz, Universitätsplatz 2, A-8010, Graz, Austria. friedrich.brunner@kfunigraz.ac.at

Cardiovascular Research
|November 14, 2003
PubMed
Abstract

Insights

Peroxynitrite impairs heart function by reducing myofilament calcium responsiveness, partly via the cGMP-dependent protein kinase pathway. This mechanism explains peroxynitrite-induced cardiac depression.

Area of Science:

  • Cardiovascular Physiology
  • Biochemistry
  • Oxidative Stress

Background:

  • Peroxynitrite, a reactive nitrogen species, is linked to heart disease.
  • Understanding its cardiac effects is crucial for therapeutic development.

Purpose of the Study:

  • Investigate the mechanism of peroxynitrite-induced cardiac depression.
  • Analyze myocardial function and intracellular calcium dynamics.

Main Methods:

  • Isolated rat hearts perfused retrogradely.
  • Measured left ventricular function and intracellular calcium ([Ca2+]i) using aequorin.
  • Administered peroxynitrite and specific pharmacological inhibitors.

Main Results:

  • Peroxynitrite decreased left ventricular developed pressure and slowed relaxation.
  • Increased [Ca2+]i, but reduced myofilament responsiveness to Ca2+.
  • cGMP-dependent protein kinase inhibition partially reversed cardiac depression.

Conclusions:

  • Peroxynitrite depresses myocardial contractility by impairing Ca2+ activation of myofilaments.
  • The cGMP/cGMP-dependent protein kinase pathway mediates part of this effect.
  • This study elucidates a key mechanism in peroxynitrite-induced cardiac dysfunction.

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