Molecular basis for the transmural distribution of the transient outward current
Molecular basis for the transmural distribution of the transient outward current
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DOI：
10.1111/j.1469-7793.2001.0001b.x
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发表时间：
2001-05-15
影响因子：
5.5
通讯作者：
Antzelevitch, C
中科院分区：
文献类型：
--
作者：
Antzelevitch, C
Regional differences in electrical properties of cardiac cells contribute to the normal function of the heart as well as to the inscription of the J wave and T wave of the ECG. Amplification of these electrical heterogeneities can lead to the development of life-threatening cardiac arrhythmias and sudden death. A number of ionic distinctions have been shown to contribute to the different action potential morphologies of epicardial, M and endocardial ventricular cells as well as to the distinctive responses of these three cell types to pharmacological agents and pathophysiological states (for reviews see Antzelevitch et al. 1999; Antzelevitch & Dumaine, 2000).Ventricular M and epicardial cells, but not endocardial cells, typically display action potentials with a prominent notch or phase 1, due to the presence of a large 4-aminopyridine (4-AP)-sensitive transient outward current (Ito). The transmural distribution of Ito is among the most striking examples of electrical heterogeneity encountered in the ventricles of the canine and human heart. Regional differences in Ito, first suggested on the basis of action potential data, have now been demonstrated using voltage clamp techniques in canine, feline, rabbit, rat and human ventricular myocytes (Fig. 1; see Antzelevitch et al. 1999 for references). Transmural differences in the magnitude of the Ito-mediated action potential notch give rise to a transmural voltage gradient, which is responsible for the inscription of the electrocardiographic J wave. Accentuation of this gradient leads to the appearance of pathophysiological J waves, ST segment elevation
