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[An nonselective cation current in rabbit ventricle myocytes]
Yan-dong Song1, Xin-chun Yang, Tai-feng Liu
1Emergency Center for Cardiopulmonary Disease, Beijing Anzhen Hospital, Capital University of Medical Science, 100029 Beijing, China.
Zhonghua Xin Xue Guan Bing Za Zhi
|November 4, 2005
Summary
Researchers identified a novel nonselective cation current in rabbit ventricular myocytes, crucial for action potential repolarization. This finding may explain and help treat cardiac arrhythmias.
Area of Science:
- Electrophysiology
- Cardiac ion channels
- Cellular cardiology
Context:
- Rabbit ventricular myocytes exhibit complex repolarization.
- The transient outward current (I(To.s)) dominates, with minor contributions from I(Kr) and I(Ks).
- Understanding all repolarizing currents is vital for cardiac function.
Purpose:
- To investigate the existence of additional currents involved in rabbit ventricular repolarization.
- To characterize the properties of any newly identified currents.
Summary:
- Using whole-cell patch-clamp, a nonselective cation current was identified in rabbit ventricular myocytes.
- This current, inhibited by Gd(3+), was modulated by Ca(2+), Mg(2+), and insulin.
- Its amplitude increased significantly upon depletion of divalent cations and with insulin addition.
Impact:
- Suggests a significant role for nonselective cation current in ventricular action potential repolarization.
- Alterations in this current could precipitate or prevent cardiac arrhythmias.
- Provides new insights into the complexity of cardiac electrophysiology.