阿米洛利对压力超负荷心肌肥厚大鼠心肌细胞内游离钙的影响

目的:观察阿米洛利预防性给药对压力超负荷心肌肥厚大鼠心肌细胞Ca²⁺]i 影响。方法:以Fura-2/AM为指示剂,测定单细胞Ca²⁺]i。结果:压力超负荷大鼠左室心肌细胞Ca²⁺]i 升高,阿米洛利和依那普利组则Ca²⁺]i 明显降低。给予KCl,NE刺激后,给药组左室心肌细胞Ca²⁺]i 的增加值明显低于左室肥厚组,百日咳毒素(PTX,100 ng·L^-1) 处理5 h 后,其静息Ca²⁺]i 无显著变化,但抑制NE诱导左室心肌细胞Ca²⁺]i 升高,该作用在左室肥厚组更明显,对KCl 刺激引起的Ca²⁺]i 升高,给药组无影响,左室肥厚组的升高值略有增加。结论:NE所致心肌细胞Ca₂₊]i 升高与PTX敏感的G 蛋白有关,肥厚时此途径亢进。

EFFECT OF AMILORIDE ON [Ca2+]i OF SINGLE MYOCARDIAL CELLS OF LEFT VENTRICLE HYPERTROPHIED RATS INDUCED BY PARTIAL LIGATION OF ABDOMINAL AORTA

AIM: To study the preventive effect of amiloride on Ca²⁺]i in single myocardial cells with the model of the left ventricle hypertrophied(LVH) rats inducd by partial ligation of the abdominal aorta. METHODS: Using Fura 2/AM as a fluoresent indicator. RESULTS: The resting Ca²⁺]i of the LVH group was increased significantly compared with that of the control group, but the Ca²⁺]i of the amiloride and enalapril groups was decreased markedly than that of the LVH group. After pretreatment with pertussis toxin (PTX, 100 ng·L^-1) for 5 h, the resting Ca²⁺]i was not changed. But the elevation of Ca²⁺]i , stimulated by the NE, was inhibited significantly, especially in the LVH group(P<0 01). CONCLUSION: The elevation of Ca²⁺]i in single myocardial cells, stimulated by NE, may relate to the PTX sensitive G protein. This pathway may increase in myocardial cells of the LVH rats.