Alteration of Na+ currents in ventricular myocytes from 1-week infarcted rabbit heart |
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Authors: | DING Chao HE Zhen-shan QI Shu-ying CUI Jun-yu YANG Li HU Li-ye SHI Qiao |
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Institution: | Department of Cardiology, the Bethune International Peace Hospital of PLA, Shijiazhuang 050082, China |
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Abstract: | AIM:To study the current density and function of Na+ channel in cells from the epicardial border zone of the 1-week infarcted rabbit heart.METHODS:Rabbits were infarcted by ligation of the left anterior descending coronary artery.1 week later, INa was recorded using whole cel patch-clamp techniques in ventricular my ocytes from infarcted heart(IZs)and compared with the INa from noninfarcted heart(NZs).RESULTS:Peak INa current density(at -30 mV) was significantly reduced in IZs(22.48±4.62 PA/PF, n=14) compared with NZs(45.50±5.33 PA/PF, n=12), P<0.01;V0.5 of the availability curve(I/Imax curve)was shifted significantly in the hyperpolarizing direction in IZs(-89.1±5.6 mV, n=6) compared with NZs (-76.2±5.3 mV, n=5), P<0.05.Recovery of INa from inactivation was significantly slower in IZs.CONCLUSIONS:INais reduced, and its kinetics are altered in IZs.These changes may underlie the altered excitability and postrepolarization refractoriness of ventricular fibers of the IZs, thus contributing to reentrant arrhymias in the infarcted heart. |
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Keywords: | Myocardial infarction Sodium channels Myocardium Rabbits |
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