Connexin 43 and Ventricular Arrhythmias

摘要

Connexin proteins (Cx) form the gap junction channels in the heart and allow for metabolic and electrical communication between cardiac myocytes. Together with membrane ion channels and tissue structure, cell-to-cell coupling via gap junctions is a key determinant of cardiac impulse propagation. The cardiac connexins Cx43, Cx40 and Cx45 are distributed in different amounts in the various regions of the heart. In ventricular tissue, Cx43 is the prominent connexin, coexisting with small amounts of Cx45, while Cx40 and Cx43 dominate in atrial tissue. In non-cardiac expression systems, the cardiac connexins may form heterotypic and heteromeric junctions with biophysical properties different from the channels formed by the individual single Cx alone. This mixture of channels is likely to have an impact on electrical cell-to-cell coupling and conduction velocity.