Different potentiating effects of imidapril and enalapril on kaolin-induced writhing reaction in mice

Abstract

Effects of the angiotensin-converting enzyme (ACE) inhibitors, imidapril and enalapril, on kaolin-induced writhing reaction, which is believed to be caused by bradykinin (BK), were examined in mice. The number of writhes was increased significantly by 200 μg/kg of imidapril and by 100 and 200 μg/kg of enalapril. The intensity of writhing reaction was significantly suppressed by 1,000 nmol/kg of icatibant, a selective bradykinin B 2 receptor antagonist, in the imidapril-, but not in the enalapril-treated groups. These results suggest that the potentiating effect of enalapril on kaolin-induced writhing reaction is greater than that of imidapril. This might depend on the difference of their inhibitory effects on BK degradation.