血管紧张素Ⅱ对心肌梗塞后心肌细胞核酸、蛋白质合成影响的研究

通过分离、培养心肌梗塞后成年大鼠的心肌细胞（MC），观察了血管紧张素Ⅱ（AngⅡ）在不同处理因素对照下，对MC核酸、蛋白质合成的影响。结果显示：在相同浓度的AngⅡ（10－7M）作用下，MI组MC的RNA和蛋白质的合成速率均显著高于假手术组（P＜0．05）。AngⅡ的上述作用，可分别被AT1受体阻滞剂Losartan、特异性AngⅡ拮抗剂1，3]AngⅡ和血管紧张素抗肽（Amg－AP）完全阻断。结果提示：AngⅡ可直接作用于非梗塞区心肌的MC，促进MC的RNA、蛋白质合成；介导AngⅡ对MC的作用是AT1受体。

THE EFFECT OF ANGIOTENSIN Ⅱ ON THE SYNTHESES OF RNA AND PROTEIN IN ISOLATED MYOCARDIAL CELLS FROM INFARCTED RATS

In the present study, the method of isotope-lablled substrate incorporation was used to investigate the effect of angiotensin Ⅱ on the synthe-ses of RNA and protein of isolated myocardial cells (MC) from rats in different conditions. The results showed that the rates of 14C-UR and 3H-Leu in-coporating in MC were significantly higher in my-ocardial infarction(MI) group than in sham-operated (SO) group, respectively. Theses effects of ang Ⅱon MCs were abolished completely by using either angiotensin receptor antagonits, Losatan, or an-giotensin anologue, 1.8Ang Ⅱ, or angiotensin an-tipeptide. Meanwhile, the mean protein cotent in a single MC was markedly higher in MI group than in SO group, too. The findings suggest that Ang Ⅱ can improve the syntheses of RNA and protein in non-infarcted myocytes, and AT1 receptor is the me-diator which transducts anR Ⅱ siRnal into MC.