Role of AT1 receptors in the renal papillary effects of acute and chronic nitric oxide inhibition

M. Clara Ortíz, Lourdes A. Fortepiani, Francisco M. Ruiz-Marcos, Noemí M. Atucha, Joaquín García-Estañ

Research output: Contribution to journalArticlepeer-review

32 Scopus citations

Abstract

Nitric oxide (NO) is a vasodilator substance controlling renal papillary blood flow (PBF) in the rat. In this study we have evaluated the role of AT1 angiotensin II receptors as modulators of the whole kidney and papillary vasoconstrictor effects induced by the acute or chronic inhibition of NO synthesis. Experiments have been performed in anesthetized, euvolemic Munich- Wistar rats prepared for the study of renal blood flow (RBF) and PBF. In normal rats, acute administration of the NO synthesis inhibitor N(ω)-nitro- L-arginine methyl ester (L-NAME) increased mean arterial pressure (MAP) and decreased RBF and PBF. Either acute or chronic treatment with the AT1 receptor blocker losartan did not modify the decreases RBF or PBF secondary to L-NAME. In animals made hypertensive by chronic inhibition of NO, basal MAP was higher, whereas RBF and PBF were lower than in the controls. In these animals, acute or chronic administration of losartan decreased MAP and increased both RBF and PBF significantly. These results indicate that, under normal conditions, the decreases in RBF or PBF induced by the acute inhibition of NO synthesis are not modulated by AT1-receptor stimulation. However, the arterial hypertension, renal vasoconstriction, and reduced PBF present in chronic NO-deficient hypertensive rats is partially due to the effects of angiotensin II, via stimulation of AT1-receptors.

Original languageEnglish (US)
Pages (from-to)R760-R766
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume274
Issue number3 43-3
StatePublished - Mar 1998
Externally publishedYes

Keywords

  • Angiotensin II
  • Kidney
  • Losartan
  • N(ω)-nitro-L-arginine methyl ester hypertension
  • Renal blood flow

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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