Journal article
The role of bradykinin, AT2 and angiotensin 1–7 receptors in the EDRF-dependent vasodilator effect of angiotensin II on the isolated mesenteric vascular bed of the rat
British journal of pharmacology, Vol.141(5), pp.860-866
03/2004
DOI: 10.1038/sj.bjp.0705669
PMCID: PMC1574258
PMID: 14757704
Abstract
The mechanisms involved in the vasodilator actions of angiotensin II (Ang II) have not yet been completely elucidated. We investigated the potential mechanisms that seem to be involved in the Ang II vasodilator effect using rat isolated mesenteric vascular bed (MVB).
Under basal conditions, Ang II does not affect the perfusion pressure of MVB. However, in vessels precontracted with norepinephrine, Ang II induces vasodilation followed by vasoconstriction. Vasoconstrictor, but not the vasodilation of Ang II, is inhibited by AT
1
antagonist (losartan). The vasodilator effect of Ang II was not inhibited by AT
2
, angiotensin IV and angiotensin 1–7 receptor antagonists alone (PD 123319, divalinal, A 779, respectively).
The vasodilator effect of Ang II is significantly reduced by endothelial removal (deoxycholic acid), but not by indomethacin. Inhibition of NO-synthase by
N
G
-nitro-
L
-arginine methyl ester (
L
-NAME) and guanylyl cyclase by 1H-[1,2,3] oxadiazolo [4,4-a] quinoxalin-1-one (ODQ) reduces the vasodilator effect of Ang II. This effect is also reduced by tetraethylammonium (TEA) or
L
-NAME, and a combination of
L
-NAME plus TEA increases the inhibitory effect of the antagonists alone. However, indomethacin does not change the residual vasodilator effect observed in vessels pretreated with
L
-NAME plus TEA.
In vessels precontracted with norepinephrine and depolarized with KCl 25 m
M
or treated with Ca
2+
-dependent K
+
channel blockers (charybdotoxin plus apamin), the effect of Ang II was significantly reduced. However, this effect is not affected by ATP and voltage-dependent K
+
channel blockers (glybenclamide and 4-aminopyridine).
Inhibition of kininase II with captopril significantly potentiates the vasodilator effect of bradykinin (BK) and Ang II in the rat MVB. The inhibitory effect of the B
2
receptor antagonist HOE 140 on the vasodilator effect of Ang II is further enhanced by PD 123319 and/or A 779.
The present findings suggest that BK plays an important role in the endothelium-dependent vasodilator effect of Ang II. Probably, the link between Ang II and BK release is modulated by receptors that bind PD 123319 and A 779.
Details
- Title: Subtitle
- The role of bradykinin, AT2 and angiotensin 1–7 receptors in the EDRF-dependent vasodilator effect of angiotensin II on the isolated mesenteric vascular bed of the rat
- Creators
- R Soares de Moura - Department of Pharmacology, State University of Rio de Janeiro, Rio de Janeiro, BrazilA C Resende - Department of Pharmacology, State University of Rio de Janeiro, Rio de Janeiro, BrazilA F Emiliano - Department of Pharmacology, State University of Rio de Janeiro, Rio de Janeiro, BrazilT Tano - Department of Pharmacology, State University of Rio de Janeiro, Rio de Janeiro, BrazilA C Mendes-Ribeiro - Department of Pharmacology, State University of Rio de Janeiro, Rio de Janeiro, BrazilM L G Correia - Department of Pharmacology, State University of Rio de Janeiro, Rio de Janeiro, BrazilL C R Marins de Carvalho - Department of Pharmacology, State University of Rio de Janeiro, Rio de Janeiro, Brazil
- Resource Type
- Journal article
- Publication Details
- British journal of pharmacology, Vol.141(5), pp.860-866
- DOI
- 10.1038/sj.bjp.0705669
- PMID
- 14757704
- PMCID
- PMC1574258
- ISSN
- 0007-1188
- eISSN
- 1476-5381
- Language
- English
- Date published
- 03/2004
- Academic Unit
- Endocrinology and Metabolism; Internal Medicine
- Record Identifier
- 9984094712802771
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