门冬氨酸钾镁对家兔肥厚性心肌细胞内钙含量的影响

目的观察口服门冬氨酸钾镁片对家兔肥厚性心肌细胞内钙含量的影响。方法将家兔随机分为假手术组、心肌肥厚组和门冬氨酸钾镁组。假手术组开腹但不行腹主动脉缩窄术，心肌肥厚组和门冬氨酸钾镁组采用腹主动脉缩窄术制备家兔心肌肥厚模型，喂养8周，制备兔左心室楔形心肌块，利用浮置玻璃微电极法同步记录楔形心肌块跨壁心电图和内、外膜心肌细胞跨膜动作电位，程序电刺激诱发室性心律失常，记录早期后除极（EAD）和尖端扭转型室速（TdP）的发生率，采用Langendorff灌流装置分离心肌细胞，应用荧光指示剂Fura-2／AM标记，SIMPLE-PCI荧光图像成像系统测量3组心肌细胞在激发波长为340am和380am时的荧光比值，并以此比值来间接反映细胞内钙含量的变化。结果①假手术组、心肌肥厚组和门冬氨酸钾镁组EAD的发生率分别为0／10、10／10和5／10，TdP的发生率分别为0／10、6／10和1／10。心肌肥厚组与假手术组相比差异有显著性意义（P〈0．05），门冬氨酸钾镁组与心肌肥厚组相比EAD和TdP的发生率明显降低，二者差异有显著性意义（均P〈0．05）。②心肌肥厚组和门冬氨酸钾镁组较假手术组荧光比值明显增大，差异有显著性意义（P〈0．05），而门冬氨酸钾镁组较心肌肥厚组的荧光比值明显减小，差异具有显著性意义（均P〈0．05）。结论肥厚心肌钙离子内流增加，形成钙超载，心律失常的发生率显著升高。门冬氨酸钾镁可以阻断慢钙通道，从而减轻钙超载，可明显降低EAD和TdP的发生率。

Effects of Potassium Magnesium Aspartate on Calcium Content of Hypertrophic Rabbit Cardiac Muscle Cells

Objective To observe the effect of potassium magnesium aspartape on the calcium content of hypertrophic rabbit cardiac muscle cells.Methods All rabbits were randomly divided into sham-operation(Sham),cardiac hypertrophy(CH) and potassium aspartate and magnesium aspartate(PAMA) groups.In CH and PAMA groups abdominal aorta was partially constricted,and in Sham group the abdominal aorta was only exposed without constriction.All rabbits were fed for 8 weeks.By using arterially perfused rabbit ventricular wedge preparations,the induced incidence of EAD and TdP was observed.Cardiac muscle cells were dissociated by using Langendorff perfusion method,and the fluorescent ratio at 340 nm and 380 nm was measured by single cell Ca2 imaging system in cardiac muscle cells.Results The induced incidence of EAD and TdP was increased in CH group as compared with that in Sham group.EAD and TdP in CH group were significantly suppressed by potassium aspartate and magnesium aspartate.The fluorescent ratio in CH and PAMA groups was significantly increased as compared with that in Sham group,and that in PAMA group was significantly decreased as compared with that in Sham group.Conclusion The calcium content and the incidence of arrhythmias were increased in hypertrophic rabbit cardiac muscle cells.Potassium magnesium aspartate can decrease the cellular calcium content and the incidence of arrhythmias in rabbits with cardiac hypertrophy.