Influence of cyclosporine A on atrial L-type calcium channel alpha1c subunit in a canine model of atrial fibrillation / 中华心血管病杂志

ABSTRACT

<p><b>OBJECTIVE</b>To investigate the impact of cyclosporine A (CsA) on atrial expression change of L-type calcium channel alpha1c subunit in a canine model of atrial fibrillation (AF).</p><p><b>METHODS</b>AF was induced by rapid atrial pacing (400 beats/min) for 8 weeks in adult male dogs and placebo (n = 6) or CsA (5 mg x kg(-1) x d(-1), n = 6) were orally administered to these animals. Sham operated animals served as normal controls (n = 6). The atrial electrophysiological parameters including P wave duration, atrial effective refractory period (AERP) were recorded and analyzed at baseline and 8 weeks later. Animals were scarified at 8 weeks post final electrophysiological examinations and atrial expressions of L-type calcium channel alpha1c subunit were determined by Western blot.</p><p><b>RESULTS</b>Compared to sham group, the P wave duration was significantly prolonged while AERP was significantly decreased in AF and CsA groups (all P < 0.05). AERP was significantly longer in CsA group than that in AF group (P < 0.05). L-type calcium channel alpha1c subunit expression was significantly downregulated in AF group compared to sham group (P < 0.05) and CsA significantly attenuated this downregulation (P < 0.01 vs. AF group).</p><p><b>CONCLUSION</b>CsA could attenuate the downregulation of the L-type calcium channel alpha1c subunit expression and improve the atrial electrophysiological remodeling in this canine model of AF.</p>