Document Detail


Role of endothelium in angiotensin II formation by the rat aorta and mesenteric arterial bed.
MedLine Citation:
PMID:  9283634     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We investigated the angiotensin II (Ang II)-generating system by analyzing the vasoconstrictor effect of Ang II, angiotensin J (Ang I), and tetradecapeptide (TDP) renin substrate in the absence and presence of inhibitors of the renin-angiotensin system in isolated rat aortic rings and mesenteric arterial beds with and without functional endothelium. Ang II, Ang I, and TDP elicited a dose-dependent vasoconstrictor effect in both vascular preparations that was completely blocked by the Ang II receptor antagonist saralasin (50 nM). The angiotensin converting enzyme (ACE) inhibitor captopril (36 microM) completely inhibited the vasoconstrictor effect elicited by Ang I and TDP in aortic rings without affecting that of Ang II. In contrast, captopril (36 microM) significantly reduced (80-90%) the response to bolus injection of Ang I, without affecting those to Ang II and TDP in mesenteric arteries. Mechanical removal of the endothelium greatly potentiated (70-95%) the vasoconstrictor response to Ang II, Ang I, and TDP in aortic rings while these responses were unaffected by the removal of the endothelium of mesenteric arteries with sodium deoxycholate infusion. In addition, endothelium disruption did not change the pattern of response elicited by these peptides in the presence of captopril. These findings indicate that the endothelium may not be essential for Ang II formation in rat mesenteric arteries and aorta, but it may modulate the response to Ang II. Although Ang II formation from Ang I is essentially dependent on ACE in both vessels, our results suggest the existence of an alternative pathway in the mesenteric arterial bed that may play an important role in Ang II generation from TDP in resistance but not in large vessels during ACE inhibition.
Authors:
R Leite; R Esteväo; A C Resende; M C Salgado
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Brazilian journal of medical and biological research = Revista brasileira de pesquisas médicas e biológicas / Sociedade Brasileira de Biofísica ... [et al.]     Volume:  30     ISSN:  0100-879X     ISO Abbreviation:  Braz. J. Med. Biol. Res.     Publication Date:  1997 May 
Date Detail:
Created Date:  1997-11-18     Completed Date:  1997-11-18     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8112917     Medline TA:  Braz J Med Biol Res     Country:  BRAZIL    
Other Details:
Languages:  eng     Pagination:  649-56     Citation Subset:  IM    
Affiliation:
Departamento de Farmacologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brasil.
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MeSH Terms
Descriptor/Qualifier:
Acetylcholine / metabolism
Angiotensin II / biosynthesis*
Animals
Aorta / metabolism*
Captopril / pharmacology
Endothelium / metabolism*
Male
Mesenteric Arteries / metabolism*
Peptidyl-Dipeptidase A / metabolism
Rats
Rats, Wistar
Renin-Angiotensin System / drug effects
Saralasin / pharmacology
Chemical
Reg. No./Substance:
11128-99-7/Angiotensin II; 34273-10-4/Saralasin; 51-84-3/Acetylcholine; 62571-86-2/Captopril; EC 3.4.15.1/Peptidyl-Dipeptidase A

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