title: Effect of berberine on acetylcholine-induced atrial fibrillation in rabbit.
abstract: The purpose of this study was to test the efficacy of Berberine (Ber) on atrial fibrillation (AF) induced by acetylcholine (ACh) and explore its underlying mechanisms of action. In vivo electrophysiology experiments were performed in adult anesthetized rabbits. Single atrial myocytes were isolated from rabbit hearts and action potentials recorded using patch clamp techniques. AF was induced by rapid atrial burst pacing during intravenous (IV) ACh infusion alone or with IV Ber. Compared to the Baseline, IV Ber (2 mg/kg) prolonged the RR interval and effective refractory period (195 ± 10 vs. 215 ± 11 msec; 80 ± 4 vs. 85 ± 5 msec, respectively; both P<0.05). The induced rate of sustained 1 min AF was lower during ACh infusion with Ber than during ACh infusion alone (4/10 vs. 30/35, P<0.01). The termination rate of ACh-induced AF was higher with IV Ber (1 mg/kg) than with IV saline (sustained 1 min AF: 6/8 vs. 6/20, sustained 10 min AF: 8/10 vs. 1/6, both P<0.05). ACh perfusion significantly shortened the action potential duration (APD) of isolated atrial myocytes (APD50: 152 ± 13 vs. 81 ± 10 msec; APD90: 256 ± 19 vs. 132 ± 13 msec, both P<0.01). Application of Ber reversed the APD shortening induced by ACh (APD50: 81 ± 10 vs. 134 ± 15 msec; APD90: 132 ± 13 vs: 213 ± 17 msec, both P<0.01). We conclude that Ber suppresses ACh-induced AF in the rabbit by increasing atrial effective refractory period and prolonging the APD of atrial myocytes.
authors.affiliation: Department of Cardiology, Shanghai Xuhui District Central Hospital/Shanghai Clinical Center of Chinese Academy of Sciences Shanghai, People's Republic of China.
authors.forename: Zhi-Wen
authors.initials: ZW
authors.lastname: Zhou
authors.affiliation: Department of Cardiology, Shanghai Xuhui District Central Hospital/Shanghai Clinical Center of Chinese Academy of Sciences Shanghai, People's Republic of China.
authors.forename: Hong-Chao
authors.initials: HC
authors.lastname: Zheng
authors.affiliation: Department of Cardiology, Shanghai Xuhui District Central Hospital/Shanghai Clinical Center of Chinese Academy of Sciences Shanghai, People's Republic of China.
authors.forename: Li-Fang
authors.initials: LF
authors.lastname: Zhao
authors.affiliation: Department of Cardiology, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine Shanghai, People's Republic of China.
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of Cardiology, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine Shanghai, People's Republic of China.
authors.forename: Jian-Wen
authors.initials: JW
authors.lastname: Hou
authors.affiliation: Department of Cardiology, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine Shanghai, People's Republic of China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Yu
authors.affiliation: Department of Cardiology, Shanghai Xuhui District Central Hospital/Shanghai Clinical Center of Chinese Academy of Sciences Shanghai, People's Republic of China.
authors.forename: Pi-Zhi
authors.initials: PZ
authors.lastname: Miao
authors.affiliation: Department of Cardiology, Shanghai Xuhui District Central Hospital/Shanghai Clinical Center of Chinese Academy of Sciences Shanghai, People's Republic of China.
authors.forename: Jian-Ming
authors.initials: JM
authors.lastname: Zhu
keywords: Berberine; acetylcholine; action potential duration; atrial fibrillation; effective refractory period