Regional expression of cardiac ion channels and cardiac electrical activity
نویسنده
چکیده
Important differences in electrophysiological properties have been noted between different regions of the heart. Electrophysiological heterogeneity has also been detected within different parts of a given tissue, such as the ventricular subendocardium, midmyocardium and subepicardium. Although many molecular candidates for native ionic currents have been identified, the molecular basis of most currents is not completely understood. Heterogeneity of channel protein composition might well underlie the differences observed among the properties of ionic currents or the shape of the act ion potential in different regions of the heart. Techniques such as immunocytochemistry, immunohistochemistry and Western blott ing have played an important role in identifying tissue expression of channel proteins as well as their cellular localization. This review summarizes the electrophysiological differences observed in different regions of the heart and correlates them with information regarding expression patterns of ion channel subunits that might account for regional functional variation.
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