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

EFFECT OF AMILORIDE ON [Ca 2+ ]i OF SINGLE MYOCARDIAL CELLS OF LEFT VENTRICLE HYPERTROPHIED RATS INDUCED BY PARTIAL LIGATION OF ABDOMINAL AORTA

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。

AIM: To study the preventive effect of amiloride on [Ca 2+ ]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 [Ca 2+ ]i of the LVH group was increased significantly compared with that of the control group, but the [Ca 2+ ]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 [Ca 2+ ]i was not changed. But the elevation of [Ca 2+ ]i , stimulated by the NE, was inhibited significantly, especially in the LVH group( P <0 01). CONCLUSION: The elevation of [Ca 2+ ]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.