Background - The physiological effects of ACE inhibitors may act in part through a kinin-dependent mechanism. We investigated the effect of chronic ACE-inhibitor treatment on functional kinin B1- and B2-receptor expression, which are the molecular entities responsible for the biological effects of kinins. Methods and Results - Rats were subjected to different 6-week treatments using various mixtures of the following agents: ACE inhibitor, angiotensin AT1-receptor antagonist, and B1 and B2-receptor antagonists. Chronic ACE inhibition induced both renal and vascular B1-receptor expression, whereas B2-receptor expression was not modified. Furthermore, with B1-receptor antagonists, it was shown that B1-receptor induction was involved in the hypotensive effect of ACE inhibition. Using microdissection, we prepared 10 different nephron segments and found ACE-inhibitor-induced expression of functional B1-receptors in all segments. ACE-inhibitor-induced B1-receptor induction involved homologous upregulation, because it was prevented by B1-receptor antagonist treatment. Finally, using B2-receptor knockout mice, we showed that ACE-inhibitor-induced B1-receptor expression was B2-receptor independent. Conclusions - This study provides the first evidence that chronic ACE-inhibitor administration is associated with functional vascular and renal B1-receptor induction, which is involved in ACE- inhibitor-induced hypotension. The observed B1-receptor induction in the kidney might participate in the known renoprotective effects of ACE inhibition.
- Angiotensin-converting enzyme
- Blood pressure
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine