tailieunhanh - Nitroprusside modulates pulmonary vein arrhythmogenic activity

Pulmonary veins (PVs) are the most important sources of ectopic beats with the initiation of paroxysmal atrial fibrillation, or the foci of ectopic atrial tachycardia and focal atrial fibrillation. Elimination of nitric oxide (NO) enhances cardiac triggered activity, and NO can decrease PV arrhythmogensis through mechano-electrical feedback. However, it is not clear whether NO may have direct electrophysiological effects on PV cardiomyocytes. This study is aimed to study the effects of nitroprusside (NO donor), on the ionic currents and arrhythmogenic activity of single cardiomyocytes from. | Lin et al. Journal of Biomedical Science 2010 17 20 http content 17 1 20 I NSC The cost of publication in Journal of Biomedical Science is bourne by the National Science Council Taiwan. JOURNAL OF BIOMEDICAL SCIENCE RESEARCH Open Access Nitroprusside modulates pulmonary vein arrhythmogenic activity Yung-Kuo Lin1 2 Yen-Yu Lu1 5 Yao-Chang Chen 3 Yi-Jen Chen1 2 and Shih-Ann Chen4 Abstract Background Pulmonary veins PVs are the most important sources of ectopic beats with the initiation of paroxysmal atrial fibrillation or the foci of ectopic atrial tachycardia and focal atrial fibrillation. Elimination of nitric oxide NO enhances cardiac triggered activity and NO can decrease PV arrhythmogensis through mechano-electrical feedback. However it is not clear whether NO may have direct electrophysiological effects on PV cardiomyocytes. This study is aimed to study the effects of nitroprusside NO donor on the ionic currents and arrhythmogenic activity of single cardiomyocytes from the PVs. Methods Single PV cardiomyocytes were isolated from the canine PVs. The action potential and ionic currents were investigated in isolated single canine PV cardiomyocytes before and after sodium nitroprusside 80 M using the whole-cell patch clamp technique. Results Nitroprusside decreased PV cardiomyocytes spontaneous beating rates from Hz to Hz in 9 cells P suppressed delayed afterdepolarization in 4 80 of 5 PV cardiomyocytes. Nitroprusside inhibited L-type calcium currents transient outward currents and transient inward current but increased delayed rectified potassium currents. Conclusion Nitroprusside regulates the electrical activity of PV cardiomyocytes which suggests that NO may play a role in PV arrhythmogenesis. Background Atrial fibrillation AF is the most common sustained arrhythmia in clinical medicine. The pulmonary veins PVs have been demonstrated to be an important source of the initiation of AF 1 2 and also to have a role in the .