目的 :观察钙调神经磷酸酶 (CaN)在血管紧张素Ⅱ (AngⅡ )刺激的大鼠心肌细胞肥大中的作用及其活性调节。方法 :建立AngⅡ诱导的大鼠心肌细胞肥大模型 ,观察CaN抑制剂对AngⅡ刺激的心肌细胞 [3H]-亮氨酸掺入的影响 ,以及各种因素对心肌细胞CaN酶活性的影响。结果 :10、10 0、10 0 0nmol·L-1的AngⅡ作用 12h分别使心肌细胞的CaN活性增加了 13%、5 7% (P <0 0 5 )、2 2 8% (P <0 0 1)。AngⅡ (10nmol·L-1)刺激心肌细胞 2h内 ,CaN活性与对照组无明显差异 (P <0 0 5 ) ;AngⅡ刺激心肌细胞 12h以上 ,CaN活性才明显增高 (P <0 0 5 )。Losartan(5 0 μmol·L-1)、H7(5 0 μmol·L-1)及Fura - 2 /AM(4 μmol·L-1)可明显抑制AngⅡ刺激的心肌细胞CaN活性 ;而PD980 5 9(5 0 μmol·L-1)对AngⅡ刺激的心肌细胞CaN活性无明显影响。AngⅡ (10 -7mol/L)刺激的大鼠心肌细胞 [3H]-亮氨酸掺入明显高于对照组 (P <0 0 1) ,而CaN特异性抑制剂 -环孢素A(0 5～ 5 μg/mL)可以明显抑制AngⅡ刺激的心肌细胞 [3H]-亮氨酸掺入。结论 :依赖Ca2 +/CaM活化的CaN可能在AngⅡ刺激的心肌细胞肥大中起重要作用 ;CaN的活化可能有赖于胞内Ca2 +水平的持续升高 ,另外 ,CaN的活性还可能受到蛋白激酶C等信号分子的磷酸化调节 Objective: To observe the role of calcineurin (CaN) in cardiomyocyte hypertrophy induced by angiotensin Ⅱ (Ang Ⅱ) and the regulation of its activity. Methods: The model of cardiomyocyte hypertrophy induced by Ang Ⅱ was established. The effects of CaN inhibitor on the incorporation of [3H] - leucine into cardiomyocytes stimulated by AngⅡ and the effect of various factors on the activity of CaN of cardiomyocytes were observed. Results: The effects of AngII at 10, 10, 10 nmol·L -1 for 12 h increased the CaN activity of cardiomyocytes by 13%, 57% (P <0.05), 22.8% (P <0 0) 1). There was no significant difference in the activity of CaN between AngⅡ (10nmol·L-1) and control group within 2h (P <0.05). The AngⅡ stimulated cardiomyocytes for more than 12h, CaN activity was significantly increased (P <0.05). Losartan (50 μmol·L -1), H7 (50 μmol·L -1) and Fura - 2 / AM (4 μmol·L -1) significantly inhibited Ang Ⅱ - induced CaN activity in cardiomyocytes. However, PD980 5 9 (50 μmol·L-1) had no significant effect on the CaN activity of AngⅡ-stimulated cardiomyocytes. The incorporation of [3H] -leucine in rat myocardial cells stimulated by AngⅡ (10 -7 mol / L) was significantly higher than that of the control group (P <0.01), while the CaN-specific inhibitor cyclosporine A ~ 5 μg / mL) could significantly inhibit the incorporation of [3H] -leucine into AngⅡ-stimulated cardiomyocytes. CONCLUSION: CaN dependent on Ca2 + / CaM activation may play an important role in the hypertrophy of AngⅡ-stimulated cardiomyocytes. The activation of CaN may depend on the continuous increase of intracellular Ca2 + level. In addition, the activity of CaN may be affected by protein kinase C Such as phosphorylation of signaling molecules