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Imaging Ca2+ Signals in Small Pulmonary Veins at Physiological Intraluminal Pressures
Published on: March 21, 2025
Nitroprusside modulates pulmonary vein arrhythmogenic activity.
Yung-Kuo Lin1, Yen-Yu Lu, Yao-Chang Chen
1Department of Biomedical Engineering, National Defense Medical Center, Taipei, Taiwan. bme02@mail.ndmctsgh.edu.tw.
Journal of Biomedical Science
|March 23, 2010
Summary
Nitric oxide (NO) donors like nitroprusside reduce pulmonary vein cardiomyocyte (PV) arrhythmogenesis by regulating ionic currents and suppressing abnormal electrical activity. This suggests NO plays a direct role in preventing atrial fibrillation triggers.
Area of Science:
- Cardiovascular Electrophysiology
- Cardiac Arrhythmia Mechanisms
- Nitric Oxide Signaling
Background:
- Pulmonary veins (PVs) are primary sources of ectopic beats initiating atrial fibrillation.
- Nitric oxide (NO) can reduce PV arrhythmogenesis via mechano-electrical feedback.
- Direct electrophysiological effects of NO on PV cardiomyocytes remain unclear.
Purpose of the Study:
- To investigate the direct electrophysiological effects of a nitric oxide donor, nitroprusside, on single PV cardiomyocytes.
- To assess the impact of nitroprusside on ionic currents and arrhythmogenic activity in PV cells.
Main Methods:
- Isolation of single cardiomyocytes from canine PVs.
- Whole-cell patch clamp technique to record action potentials and ionic currents.
- Application of sodium nitroprusside (80 μM) to assess its effects.
Main Results:
- Nitroprusside significantly decreased spontaneous beating rates in PV cardiomyocytes.
- Delayed afterdepolarizations were suppressed by nitroprusside.
- Nitroprusside inhibited L-type calcium, transient outward, and transient inward currents while increasing delayed rectified potassium currents.
Conclusions:
- Nitroprusside modulates the electrical activity of PV cardiomyocytes.
- These findings suggest a direct role for NO in regulating PV arrhythmogenesis.
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