Influence of Dexamethasone on Atrial Ion Currents and Their Early Ionic Tachycardia-induced Electrical Remodeling in Rabbits

Cellular Physiology and Biochemistry

关键词: Atrial fibrillation;    Inflammation;    Remodeling;    Dexamethasone;    Steroids;   

DOI  :  10.1159/000322317

学科分类：分子生物学，细胞生物学和基因

来源: S Karger AG

【 摘 要 】

Background Certain evidence points to a role of inflammation in AF pathophysiology. Thus, antiinflammatory treatment of AF is discussed. Effects of a dexamethasone treatment (7 days) on atrial ion currents (I_Ca,L, I_to, I_sus) and their tachycardia-induced remodeling were studied in a rabbit model. Methods 6 groups of 4 animals each were built. Rapid atrial pacing (600 min) was performed for 24 and 120 hours with/ without dexamethasone treatment. Ion currents were measured using whole cell patch clamp method. Results Rapid atrial pacing reduced (I_Ca,L, I_to was decreased after 24 hours but almost returned to control values after 120 hours. When dexamethasone-treated animals also underwent atrial tachypacing, pacing-induced reduction of I_Ca,L was still observed after 24 hours and was even augmented after 120 hours compared to untreated but tachypaced animals. I_to was not influenced by dexamethasone alone. In dexamethasone-treated animals, reduction of I_to was not observed after 24 hours but occurred after 120 hours of atrial tachypacing. I_sus was neither influenced by rapid atrial pacing nor by dexamethasone. Biophysical properties of all currents were affected neither by rapid atrial pacing nor by dexamethasone. Conclusion Dexamethasone influenced tachycardia-induced alterations of atrial I_to. Our experiments give evidence that - amongst other anti-inflammatory action – impact of dexamethasone on ion currents and their tachycardia-induced alterations might also play a role in treatment/prevention of AF with steroids.

【 授权许可】

CC BY-NC-ND