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Updated: May 20, 2026

Simultaneous Measurement of Mitochondrial Calcium and Mitochondrial Membrane Potential in Live Cells by Fluorescent Microscopy
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Simultaneous Measurement of Mitochondrial Calcium and Mitochondrial Membrane Potential in Live Cells by Fluorescent Microscopy

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Calcium-induced cardiac mitochondrial dysfunction is predominantly mediated by cyclosporine A-dependent mitochondrial

Chontida Yarana1, Jirapas Sripetchwandee, Jantira Sanit

  • 1Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Thailand.

Archives of Medical Research
|July 25, 2012
PubMed
Abstract

Insights

Cardiac mitochondrial calcium overload causes dysfunction primarily via the mitochondrial permeability transition pore (mPTP), not the mitochondrial calcium uniporter (MCU). Cyclosporin A (CsA) is more effective than Ru360 in preventing this overload.

Area of Science:

  • Cardiology
  • Mitochondrial Biology
  • Cellular Physiology

Background:

  • Cardiac mitochondrial calcium overload is a key factor in heart dysfunction, cell death, and arrhythmia.
  • This overload is linked to mitochondrial permeability transition, reactive oxygen species (ROS) production, and membrane potential (ΔΨm) dissipation.

Purpose of the Study:

  • To investigate the mechanistic link between calcium overload, oxidative stress, mPTP, and MCU in cardiac mitochondria.
  • To determine the relative roles of mPTP and MCU in calcium-induced mitochondrial dysfunction.
  • To evaluate the protective effects of mPTP and MCU blockers against calcium overload.

Main Methods:

  • Isolated cardiac mitochondria were exposed to varying calcium concentrations (5-200 μM).
  • The effects of Cyclosporin A (CsA), an mPTP inhibitor, and Ru360, an MCU inhibitor, were assessed.

Main Results:

  • High calcium concentrations (≥100 μM) induced significant mitochondrial swelling and ΔΨm collapse.
  • ROS production increased only slightly, suggesting it's not the primary driver of dysfunction.
  • Inhibition of MCU by Ru360 offered limited protection against calcium-induced mitochondrial dysfunction.

Conclusions:

  • Cardiac mitochondrial dysfunction due to calcium overload is predominantly mediated by the mPTP.
  • The mPTP plays a more critical role than MCU in this process.
  • CsA demonstrates greater efficacy than Ru360 in preventing calcium-induced cardiac mitochondrial dysfunction.

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