EPR quantification of vascular nitric oxide production in genetically modified mouse models

Nitric Oxide. 2004 May;10(3):156-61. doi: 10.1016/j.niox.2004.04.003.


With increasing use of genetically modified mice to study endothelial nitric oxide (NO) biology, methods for reliable quantification of vascular NO production by mouse tissues are crucial. We describe a technique based on electron paramagnetic resonance (EPR) spectroscopy, using colloid iron (II) diethyldithiocarbamate [Fe(DETC)2], to trap NO. A signal was seen from C57BL/6 mice aortas incubated with Fe(DETC)2, that increased 4.7-fold on stimulation with calcium ionophore A23187 [3.45+/-0.13 vs 0.73+/-0.13au (arbitrary units)]. The signal increased linearly with incubation time (r(2) = 0.93), but was abolished by addition of N(G)-nitro-l-arginine methyl ester (L-NAME) or endothelial removal. Stimulated aortas from eNOS knockout mice had virtually undetectable signals (0.14+/-0.06 vs 3.17+/-0.21 au in littermate controls). However, the signal was doubled from mice with transgenic eNOS overexpression (7.17+/-0.76 vs 3.37+/-0.43 au in littermate controls). We conclude that EPR is a useful tool for direct NO quantification in mouse vessels.

Publication types

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

MeSH terms

  • Animals
  • Aorta / chemistry
  • Aorta / metabolism*
  • Aorta, Thoracic / enzymology
  • Electron Spin Resonance Spectroscopy*
  • Mice
  • Mice, Knockout
  • Mice, Transgenic
  • Models, Animal
  • Nitric Oxide Synthase / analysis
  • Nitric Oxide Synthase / biosynthesis*
  • Nitric Oxide Synthase / genetics


  • Nitric Oxide Synthase