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目的 澄清莲心总碱 (TAL)与氨基糖苷类抗生素的共同化学结构带正电的氨基是否使之具有抗牵张性心律失常的共同效应。方法 通过膨胀心室腔内的球囊、夹闭升主动脉和牵拉乳头肌建立心律失常、动作电位时程的缩短和触发活动的模型。采用离体心电图、细胞内微电极和在体单相动作电位的标准技术进行记录。结果 ①TAL和甲基莲心总碱 (TMAL) (2 .5 ,5和 10 μmol·L- 1)能剂量依赖性的缩短大鼠离体心脏牵张性心律失常的持续时间 ,从对照组的 (2 .16± 0 .38)s减少到 (1.5 3± 0 .14 ) ,(0 .93± 0 .2 1) ,(0 .5 2± 0 .35 )s (TAL )和(1.5 9± 0 .16 ) ,(0 .94± 0 .2 1) ,(0 .79± 0 .15 )s(TMAL)。②在麻醉豚鼠 ,TAL 2 .3mg·kg- 1iv和TMAL 2 .6mg·kg- 1iv能显著抑制夹闭主动脉引起的单相动作电位 5 0 %和 90 %复极时程的缩短及触发活动的发生率 ,分别从 (2 8.9± 8.1) %减少到(5 .4± 1.2 ) %和 (10 .8± 2 .3) %。③TAL和TMAL也能显著抑制牵拉豚鼠乳头肌所致的动作电位 5 0 %和 90 %复极时程的缩短。结论 TAL和TMAL能抑制牵张性心律失常和牵张引起的动作电位的改变 ,这种作用可能是通过阻断牵张活化的离子通道实现的。
Objective To clarify whether the positively charged amino groups of the common chemical structure of TAL and aminoglycoside antibiotics have the common effect of anti-stretch arrhythmia. Methods A model of arrhythmia, shortening of action potential duration, and triggering activity was established by expanding the balloon in the ventricular cavity, clamping the ascending aorta, and pulling the papillary muscles. Recordings were performed using standard techniques for electrocardiography, intracellular microelectrodes and in vivo monophasic action potentials. Results 1 TAL and TML (TMAL) (2.5, 5, and 10 μmol·L-1) energy dose-dependently shortened the duration of isolated cardiac atrial arrhythmias in rats from the control group ( 2.16 ± 0 .38)s decreased to (1.5 3 ± 0 .14), (0.93 ± 0.21), (0.52 ± 0.35) s (TAL), and (1.5 9 ± 0 .16), (0.99 ± 0.21), (0.79 ± 0.15) s (TMAL). 2In anaesthetized guinea pigs, TAL 2.3 mg·kg-1 iv and TMAL 2.6 mg·kg-1 iv significantly inhibited shortening and triggering activity of 50% and 90% repolarization durations induced by clipped aorta. The incidence of the disease decreased from (28.9±8.1)% to (5.4±1.2)% and (10.8%±2.3%). 3TAL and TAL also significantly inhibited the shortening of the action potentials induced by guinea pig papillary muscle 50% and 90% repolarization. Conclusion TAL and TMAL can inhibit the action potential changes caused by stretch arrhythmia and distraction. This effect may be achieved by blocking stretch-activated ion channels.