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Activation of the renin-angiotensin system plays an important role in the pathogenesis of atrial electrical remodeling. More and more evidence supports that small conductance calcium activated potassium channels (SK channels) are closely related with atrial arrhythmia. However, little is known about the electrophysiological effects of Ang II on SK channels. The aim of this study was to determine the effects of Angiotensin II on SK channels in human atrial myocytes.
Whole-cell patch clamp technique was used to record SK current.
SK current densities were significantly increased in patients with CAF compared to patients with Sinus rhythm (SR). Ang II (1μmol/L) decreased the current density of SK channels both in SR group and CAF group. The decreased proportion of SK current densities in CAF were larger than in SR. Ang II induced inhibition of the SK current was abolished by PD123 319 (10 μmol/L, the AT2 receptor antagonist), but not by valsartan (10μmol/L, the AT1 receptor antagonist).
Ang II exhibits an inhibitory effect on SK currents via AT2 receptors in huaman atrial, are larger in CAF group than in SR group. This is a potential mechanism by which elevated levels of Ang II are involved in the occurrence of atrial electrical remodeling.