Role of PGI2 and effects of ACE inhibition on the bradykinin potentiation by angiotensin-(1-7) in resistance vessels of SHR

Autor(es)

Fernandes‚ L. ; Fortes‚ Z. B. ; Casarini‚ D. E. ; Nigro‚ D. ; Tostes‚ R. C. A. ; Santos‚ R. A. S. ; de Carvalho‚ M. H. C.

• Tipo de documento: Artigo Científico
• Fonte: Regulatory Peptides; v. 127, n. 1/3, p. 183-189, Apr. 2005.
• Área do conhecimento: Ciências Biológicas - Farmacologia
• Assunto(s): Bradicinina Inibidores da enzima conversora da angiotensina Peptídeos Hipertensão

Resumo

The present study determined the participation of PGI2 in the angiotensin-(1-7) [Ang-(1-7)]/bradykinin (BK) interaction, in the presence and absence of Angiotensin Converting Enzyme (ACE) inhibition, trying to correlate it with tissue levels of both peptides. The isolated mesenteric arteriolar bed of Spontaneously Hypertensive Rats (SHR) was perfused with Krebs or Krebs plus enalaprilat (10 nM), and drugs were injected alone or in association. BK (10 ng)-induced relaxation was potentiated by Ang-(1-7) (2.2 μg) in the presence or absence of enalaprilat. Ang-(1-7) receptor blockade [A-779 (4.8 μg)] did not interfere with the BK effect in preparations perfused with normal Krebs, but reversed the increased BK relaxation observed after ACE inhibition. PGI2 release by mesenteric vessels was not altered by BK or Ang-(1-7) alone, but was increased when both peptides were injected in association, in the absence or in the presence of enalaprilat. ACE inhibition caused a 2-fold increase in the BK tissue levels, and a significant decrease in the Ang-(1-7) values. We conclude that endogenous Ang-(1-7) has an important contribution to the effect of ACE inhibitors participating in the enhancement of BK response. The mechanism of Ang-(1-7) potentiating effect probably involves an increased production of PGI2. Our results suggest that a different enzymatic pathway (non-related to ACE) is involved in the local Ang-(1-7) metabolism. (AU)

• Processo FAPESP: 01/12294-1 - Analise funcional e molecular de receptores b1 de cininas na hipertensao arterial.
• Beneficiário: Liliam Fernandes
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado