[Influence of cyclosporine A on atrial L-type calcium channel alpha1c subunit in a canine model of atrial fibrillation].
OBJECTIVE
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).


METHODS
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.


RESULTS
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).


CONCLUSIONS
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.
Huang
Ya
Y
Institute of Geriatric Cardiology, Chinese PLA General Hospital, Beijing 100853, China.
Lu
Cai-Yi
CY
Yan
Wei
W
Gao
Lei
L
Chen
Qi
Q
Zhang
Ya-Jing
YJ
D000818:Animals; D001281:Atrial Fibrillation / Q000188:drug therapy / Q000378:metabolism*; D020746:Calcium Channels, L-Type / Q000378:metabolism*; D016572:Cyclosporine / Q000494:pharmacology* / Q000627:therapeutic use; D004285:Dogs; D006325:Heart Atria / Q000378:metabolism* / Q000503:physiopathology; D008297:Male
D020746:Calcium Channels, L-Type; C419385:L-type calcium channel alpha(1C); D016572:Cyclosporine