Disruption of Physiological Balance Between Nitric Oxide and Endothelium-Dependent Hyperpolarization Impairs Cardiovascular Homeostasis in Mice

Arterioscler Thromb Vasc Biol. 2016 Jan;36(1):97-107. doi: 10.1161/ATVBAHA.115.306499. Epub 2015 Nov 5.


Objective: Endothelium-derived nitric oxide (NO) and endothelium-dependent hyperpolarization (EDH) play important roles in modulating vascular tone in a distinct vessel size-dependent manner; NO plays a dominant role in conduit arteries and EDH in resistance vessels. We have recently demonstrated that endothelial NO synthase (eNOS) is functionally suppressed in resistance vessels through caveolin-1 (Cav-1)-dependent mechanism, switching its function from NO to EDH/hydrogen peroxide generation in mice. Here, we examined the possible importance of the physiological balance between NO and EDH in cardiovascular homeostasis.

Approach and results: We used 2 genotypes of mice in which eNOS activity is genetically upregulated; Cav-1-knockout (Cav-1-KO) and endothelium-specific eNOS transgenic (eNOS-Tg) mice. Isometric tension recordings and Langendorff experiments with isolated perfused hearts showed that NO-mediated relaxations were significantly enhanced, whereas EDH-mediated relaxations were markedly reduced in microcirculations. Importantly, impaired EDH-mediated relaxations of small mesenteric arteries from Cav-1-KO mice were completely rescued by crossing the mice with those with endothelium-specific overexpression of Cav-1. Furthermore, both genotypes showed altered cardiovascular phenotypes, including cardiac hypertrophy in Cav-1-KO mice and hypotension in eNOS-Tg mice. Finally, we examined cardiac responses to chronic pressure overload by transverse aortic constriction in vivo. When compared with wild-type mice, both Cav-1-KO and eNOS-Tg mice exhibited reduced survival after transverse aortic constriction associated with accelerated left ventricular systolic dysfunction, reduced coronary flow reserve, and enhanced myocardial hypoxia.

Conclusions: These results indicate that excessive endothelium-derived NO with reduced EDH impairs cardiovascular homeostasis in mice in vivo.

Keywords: caveolin-1; endothelium; endothelium-dependent hyperpolarization factor; nitric oxide.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biological Factors / metabolism*
  • Cardiomegaly / enzymology
  • Cardiomegaly / genetics
  • Cardiomegaly / pathology
  • Caveolin 1 / deficiency
  • Caveolin 1 / genetics
  • Cell Hypoxia
  • Coronary Circulation
  • Dose-Response Relationship, Drug
  • Endothelium, Vascular / drug effects
  • Endothelium, Vascular / enzymology*
  • Endothelium, Vascular / physiopathology
  • Enzyme Inhibitors / pharmacology
  • Genotype
  • Homeostasis
  • Hypotension / enzymology
  • Hypotension / genetics
  • Hypotension / physiopathology
  • Isolated Heart Preparation
  • Male
  • Membrane Potentials
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Microcirculation
  • Myocardium / metabolism
  • Nitric Oxide / metabolism*
  • Nitric Oxide Synthase Type III / antagonists & inhibitors
  • Nitric Oxide Synthase Type III / biosynthesis
  • Nitric Oxide Synthase Type III / genetics
  • Phenotype
  • Signal Transduction
  • Systole
  • Time Factors
  • Up-Regulation
  • Vasodilation* / drug effects
  • Vasodilator Agents / pharmacology
  • Ventricular Dysfunction, Left / enzymology
  • Ventricular Dysfunction, Left / genetics
  • Ventricular Dysfunction, Left / physiopathology
  • Ventricular Function, Left*


  • Biological Factors
  • Cav1 protein, mouse
  • Caveolin 1
  • Enzyme Inhibitors
  • Vasodilator Agents
  • endothelium-dependent hyperpolarization factor
  • Nitric Oxide
  • Nitric Oxide Synthase Type III
  • Nos3 protein, mouse