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Voltage-Dependent Potassium Current Recording on H9c2 Cardiomyocytes via the Whole-Cell Patch-Clamp Technique
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Calcium-activated potassium current modulates ventricular repolarization in chronic heart failure
Ingrid M Bonilla1, Victor P Long1, Pedro Vargas-Pinto2
1College of Pharmacy, The Ohio State University, Columbus, Ohio, United States of America; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, United States of America.
Plos One
|October 2, 2014
Summary
Blocking the calcium-activated potassium current (I(KCa)) in heart failure ventricular myocytes causes arrhythmias. This suggests I(KCa) is crucial for maintaining ventricular repolarization stability during heart failure.
Area of Science:
- Cardiovascular Physiology
- Cardiac Electrophysiology
- Pharmacology
Background:
- The role of the calcium-activated potassium current (I(KCa)) in cardiac repolarization is debated.
- Its significance as a therapeutic target in heart conditions remains unclear.
Purpose of the Study:
- To investigate the electrophysiologic impact of I(KCa) blockade in canine and human cardiac myocytes.
- To assess I(KCa)'s role in controls, chronic heart failure (HF), and HF with atrial fibrillation.
Main Methods:
- Perforated patch recordings of action potentials in atrial and ventricular myocytes.
- Utilized apamin (100 nM) to block I(KCa).
- Studied canine models of HF and human myocytes from failing hearts.
Main Results:
- I(KCa) blockade did not alter atrial myocyte action potentials in any group.
- Ventricular repolarization was unaffected by I(KCa) blockade in controls.
- In HF, I(KCa) blockade prolonged ventricular repolarization and induced instability and early afterdepolarizations.
Conclusions:
- I(KCa) blockade in ventricular myocytes leads to cellular arrhythmias during heart failure.
- I(KCa) plays a vital role in maintaining ventricular repolarization stability in chronic heart failure.
- Future antiarrhythmic therapies require evaluation in both atrial and ventricular tissues.
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