Role of ACE and NEP in bradykinin-induced relaxation and contraction response of isolated porcine basilar artery

Abstract

The aim of the present study was to clarify the role of angiotensin converting enzyme (ACE) and neutral endopeptidase (NEP) in bradykinin (BK)-induced relaxation and contraction of isolated porcine basilar artery by measuring isometric tension, ACE and NEP activities and their localization. BK induced endothelium-dependent relaxation followed by contraction; however, in the presence of indomethacin BK induced relaxation but not contraction, in contrast, in the presence of L-nitro-arginine BK induced contraction but not relaxation. Captopril and thiorphan increased the p D(2) value for BK-induced relaxation from 8.11 to 9.55 and the p A(2) value for [Thi(5,8), D-Phe(7)]-BK (a B(2)-receptor antagonist) from 6.95 to 7.59. The same treatment increased the p D(2) value for BK-induced contraction from 7.93 to 8.97 and the p A(2) value for [Thi(5,8), D-Phe(7)]-BK from 6.86 to 7.50. Captopril inhibited ACE activity with an IC(50) of 38.0 nM, and thiorphan inhibited NEP and ACE activities with an IC(50) of 1.4 nM and 295.0 nM, respectively. Endothelial denudation decreased the ACE and NEP activities by 76.7% and 15.9%, respectively, and ACE mRNA level by 59.4%, but had no significant effect on NEP mRNA level. These results suggest that BK-induced relaxation and contraction in the porcine basilar artery are enhanced by captopril and thiorphan which predominantly inhibit ACE activity localized on endothelial cells.

Potentiation of des-Arg9-Kallidin-Induced Vasoconstrictor Responses by Metallopeptidase Inhibition in Isolated Human Umbilical Artery

“…at ASPET Journals on May 10, 2018 jpet.aspetjournals.org that ACE inhibition potentiates in vitro effects of BK in vascular tissues (Miyamoto et al, 2002). However, in our model, ACE inhibition by captopril did not modify DAKDinduced contractile responses.…”

“…Additionally, in functional studies, NEP's ability to inactivate different vasoactive peptides in isolated smooth muscle preparations has been evaluated. For instance, BKinduced relaxation of vascular as well as bronchial smooth muscle has been shown to be potentiated by inhibition of NEP (Frossard et al, 1990;Miyamoto et al, 2002). However, to our knowledge, no reports have been made regarding any functional relevance of NEP on the BKB 1 receptor agonists' elicited responses.…”

Neutral Endopeptidase Up-Regulation in Isolated Human Umbilical Artery: Involvement in Desensitization of Bradykinin-Induced Vasoconstrictor Effects

“…In other experiments, HUA rings were incubated for 2, 3, or 5 h and then sequentially challenged with 1 M des-Arg 10 -kallidin, 0.1 M BK, and 10 M serotonin (5-HT). Whenever necessary, effective inhibitory doses of peptidase inhibitors were used: 1 M captopril (ACE inhibitor, IC 50 38 nM) (Miyamoto et al, 2002), 10 M phosphoramidon (NEP inhibitor, IC 50 10 nM) (Loffler, 2000), 10 M thiorphan (NEP inhibitor, IC 50 1.4 nM) (Miyamoto et al, 2002), and 10 M amastatin [aminopeptidase M (APM) inhibitor, IC 50 50 nM] (Proud et al, 1987) were applied 30 min before the addition of BKB 2 and BKB 1 receptor agonists. The concentrations of amastatin, captopril, and phosphoramidon used in this study were previously shown to produce the inhibition of des-Arg 10 -kallidin inactivation as assessed by functional contractility studies in HUA (Pelorosso et al, 2005).…”

“…On the other hand, ECE is highly resistant to inhibition by thiorphan (IC 50 higher than 200 M) (Hoang and Turner, 1997). Nevertheless, it is important to note that thiorphan is also able to inhibit ACE (IC 50 295 nM) (Miyamoto et al, 2002). Therefore, all experiments involving thiorphan were carried out in presence of 1 M captopril to avoid possible ACE interference.…”

Effects of taxifolin on the activity of angiotensin-converting enzyme and reactive oxygen and nitrogen species in the aorta of aging rats and rats treated with the nitric oxide synthase inhibitor and dexamethasone

“…The ACE activity was determined by measuring the hydrolysis of hippuryl-L-histidyl-L-leucine (Hip-HisLeu) using the method of Ackermann et al (1998), with a modification from Miyamoto et al (2002). Briefly, isolated rat aorta sections were placed in Hank's-HEPES solution, pH 7.4 (450 μl), and incubated for 10 min at 37°C with shaking (25 Hz, amplitude 1 mm) for adaptation before the addition of the ACE substrate.…”