大鼠在体血管紧张素Ⅰ转化酶活性检测新方法

A new bioassay method to estimate the rat angiotensin Ⅰ converting engyme activity in vivo

目的 用血管紧张素Ⅰ转化酶 (ACE)抑制药雷米普利 (Ram)建立一种新的大鼠在体ACE生物活性检测方法。方法 比较不同剂量 (0 0 5、0 1mg·kg- 1 ,iv)Ram在给药后1、2 4、48h对血管紧张素Ⅰ (AngⅠ )升压和缓激肽 (BK)降压效应的影响 ,以AngⅠ的升压百分率 (% )或BK的降压百分率 (% )间接反映ACE活性变化。结果 大鼠给予Ram后1、2 4h ,静脉注射AngⅠ和心肌匀浆上清液 (含AngⅠ )的升压作用均降低 (P <0 0 5) ,且呈剂量依赖性 ,但在 48h后Ram对AngⅠ和心肌匀浆上清液 (含AngⅠ )的升压作用无影响。比较给予Ram后 1hAngⅠ的升压作用和缓激肽(BK)的降压作用 ,发现BK的降压作用比AngⅠ升压作用更明显 (P <0 0 5)。结论 大鼠静脉注射Ram后 2 4h内心肌和血浆中ACE活性显著被抑制 ,48h后ACE活性基本恢复 ;AngⅠ升压、BK降压效应的变化可作为ACE生物活性的在体检测指标 。

AIM To establish a new bioassay method for estimating the rat angiotensin Ⅰ converting engyme (ACE) activity in vivo by using ramipril (Ram), a ACE inhibitor. METHODS The change in mean arterial pressure induced by angioteuasin Ⅰ (AngⅠ) or bradykinin (BK) was measured before and 1, 24, 48 h after pretreatment with Ram (0 05,0 1 mg·kg -1 ,iv). The ACE activity was expressed by the pressor effect (%)of AngⅠ or the depressor effect (%) of BK. RESULTS The pressor effects of AngⅠ or the supernatant fraction of heart tissue homogenate containing AngⅠ were siginificantly reduced 1 h and 24 h after pretreatment with Ram, but not 48 h after pretreatment with Ram. In comparison of the depressor response of BK vs pressor response of AngⅠ 1 h after pretreatment with Ram,it was shown that the depressor effect of BK is more sensitive than the pressor effect of AngⅠ( P <0 05). CONCLUSIONS Ram maintains inhibitory effect to ACE in the plasma or myocardial tissues within 24 h in dose dependent manner. But the inhibition disappeares by 48 h. As a parameter of ACE inhibition,the BK induced depressor effect is more sensitive than the pressor effect of AngⅠ.