Flow-dependent dilation mediated by endogenous kinins requires angiotensin AT2 receptors

Circ Res. 2004 Jun 25;94(12):1623-9. doi: 10.1161/01.RES.0000131497.73744.1a. Epub 2004 May 6.

Abstract

The vascular kallikrein-kinin system contributes to about one third of flow-dependent dilation in mice carotid arteries, by activating bradykinin B2 receptors coupled to endothelial nitric oxide (NO) release. Because the bradykinin/NO pathway may mediate some of the effects of angiotensin II AT2 receptors, we examined the possible contribution of AT2 receptors to the kinin-dependent response to flow. Changes in outer diameter after increases in flow rate were evaluated in perfused arteries from wild-type animals (TK+/+) and in tissue kallikrein-deficient mice (TK-/-) in which the presence of AT2 receptor expression was verified. Saralasin, a nonselective angiotensin II receptor antagonist, impaired significantly flow-induced dilation in TK+/+, whereas it had no effect in TK-/- mice. In both groups, blockade of AT1 receptors with losartan or candesartan did not affect the response to flow. Inhibition of AT2 receptors with PD123319 reduced significantly flow-induced dilation in TK+/+ mice, but had no significant effect in TK-/- mice. Combining PD123319 with the bradykinin B2 receptor antagonist HOE-140 had no additional effect to AT2 receptor blockade alone in TK+/+ arteries. Flow-dependent-dilation was also impaired in AT2 receptor deficient mice (AT2-/-) when compared with wild-type littermates. Furthermore, HOE-140 significantly reduced the response to flow in the AT2+/+, but not in AT2-/- mice. In conclusion, this study demonstrates that the presence of functional AT2 receptors is necessary to observe the contribution of the vascular kinin-kallikrein system to flow-dependent dilation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid / pharmacology
  • Acetylcholine / pharmacology
  • Angiotensin II Type 1 Receptor Blockers / pharmacology
  • Angiotensin II Type 2 Receptor Blockers
  • Animals
  • Benzimidazoles / pharmacology
  • Biphenyl Compounds
  • Bradykinin / analogs & derivatives*
  • Bradykinin / pharmacology
  • Bradykinin B2 Receptor Antagonists
  • Carotid Arteries / drug effects*
  • Carotid Arteries / physiology
  • Carotid Arteries / ultrastructure
  • Hemorheology
  • Imidazoles / pharmacology
  • Losartan / pharmacology
  • Male
  • Mesenteric Arteries / drug effects
  • Mesenteric Arteries / physiology
  • Mesenteric Arteries / ultrastructure
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Phenylephrine / pharmacology
  • Pyridines / pharmacology
  • Receptor, Angiotensin, Type 2 / deficiency
  • Receptor, Angiotensin, Type 2 / genetics
  • Receptor, Angiotensin, Type 2 / physiology*
  • Receptor, Bradykinin B2 / physiology
  • Tetrazoles / pharmacology
  • Tissue Kallikreins / deficiency
  • Tissue Kallikreins / genetics
  • Tissue Kallikreins / physiology*
  • Vasodilation / drug effects
  • Vasodilation / physiology*
  • Vasodilator Agents / pharmacology

Substances

  • Angiotensin II Type 1 Receptor Blockers
  • Angiotensin II Type 2 Receptor Blockers
  • Benzimidazoles
  • Biphenyl Compounds
  • Bradykinin B2 Receptor Antagonists
  • Imidazoles
  • Pyridines
  • Receptor, Angiotensin, Type 2
  • Receptor, Bradykinin B2
  • Tetrazoles
  • Vasodilator Agents
  • PD 123319
  • Phenylephrine
  • 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid
  • icatibant
  • Tissue Kallikreins
  • Losartan
  • Acetylcholine
  • candesartan
  • Bradykinin