A new bioassay method to estimate the rat angiotensin Ⅰ converting engyme activity in vivo / 中国药理学通报

ABSTRACT

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