摘要
用微电极技术观察了小檗碱对过氧化氢所致的动作电位改变的影响。过氧化氢1和10mmol/L灌流豚鼠乳头肌80min导致一系列的动作电改变,可分三期。起初5min动作电位时程明显延长(延长期);6～30min动作电位时程迅速缩短、幅度和0相最大上升速率下降、膜去极化和部分标本出现延迟后除极及期外收缩(抑制期);31～80min动作电位各参数逐渐有所回升(回升期)。加过氧化氢前30min起予小檗碱24.5μmol/L不能抑制动作电位的一系列改变。结果表明自由基所致的心肌细胞电生理改变可能是再灌注心律失常的发生机制之一,小檗碱无直接的抗氧自由基作用。
Standard microelectrode techniques were used to study the effect of berberine on hydrogen peroxide (H_2O_2) induced alterations of electrical activity. Perfusion of guinea pig papillary muscles with H_2O_2 (1 and 10 mmol/L) for 80 min resulted in a reproducible se quence of changes in action potentials which could be divided into 3 stages. The action potential duration increased significantly during the first 5 min. Continued perfusion (6-30 min) caused rapid action potential shortening accompanied by resting membrane depolarization, reduction in action potential amplitude and maximum rate of depolarization. These changes were accompanied by delayed after-depolarization and after-contractions in several preparations (stage Ⅱ). After the stage Ⅱ(31-80 min), all values of action potential showed a further sustained increase (stage Ⅲ). Perfusion with berberine (24.5μmol/L) 30 min before the addition of H_2O_2 did not attenuated the develoyment of the changes in action potential. We suggest that the myocardial electrophysiological phenomenon caused by H_2O_2 may contribute to the genesis of reperfusion arrhythmias and berberine has no direct scavenging effect on oxygen free radicals.
出处
《上海医学》
CAS
CSCD
北大核心
1992年第9期524-526,共3页
Shanghai Medical Journal
关键词
过氧化氢
小檗碱
心肌动作电位
Hydrogen peroxide
berberine: cardiac action potentials
