In vivo nitric oxide detection in the septic rat brain by electron paramagnetic resonance.
To detect nitric oxide (NO) in the rat brain during lipopolysaccharide (LPS)-induced sepsis, electron paramagnetic resonance (EPR) was employed with the NO trapping technique, using an iron and N,N-diethyldithiocarbamate (DETC) complex. An X-band (about 9.5 GHz) EPR system detected a triplet signal (g = 2.038) derived from an NO-Fe-DETC complex being superimposed on the g(perpendicular) signal of Cu-DETC complex at liquid nitrogen temperature. The height of the triplet signal peaked seven hours after injection of 40 mg/kg of LPS, and over 25 x 10(4) U/kg of IFN-gamma enhanced the LPS-induced NO formation. Pretreatment with N(G)-monomethyl-L-arginine (NMMA), an NO synthase inhibitor, deleted only the triplet signal. A triplet signal (g(iso) = 2.040, aN = 1.28 mT) derived from the NO-Fe-DETC complex was also observed at ambient temperature. Then, a home-built 700 MHz EPR system was used to detect an NO signal in the septic rat brain in vivo. We successfully monitored the NO-Fe-DETC signal in the head region of a living rat under the condition that provided maximum height of the NO-Fe-DETC signal in the X-band EPR study. Pretreatment with NMMA again deleted the NO-Fe-DETC signal. This is the first EPR observation of endogenous NO in the brain of living rats.
Suzuki
Y
Y
Division of Bioinorganic Chemistry, Institute for Life Support Technology, Yamagata Technopolis Foundation, Matsuei, Japan.
Fujii
S
S
Numagami
Y
Y
Tominaga
T
T
Yoshimoto
T
T
Yoshimura
T
T
D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D001927:Brain Diseases / Q000139:chemically induced / Q000378:metabolism*; D002614:Chelating Agents / Q000494:pharmacology; D004050:Ditiocarb / Q000378:metabolism; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004926:Escherichia coli; D005260:Female; D007501:Iron / Q000494:pharmacology; D008070:Lipopolysaccharides; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D051381:Rats; D017207:Rats, Sprague-Dawley; D018805:Sepsis / Q000139:chemically induced / Q000378:metabolism*; D019097:Spin Trapping; D019323:omega-N-Methylarginine / Q000494:pharmacology
D002614:Chelating Agents; D004791:Enzyme Inhibitors; D008070:Lipopolysaccharides; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D004050:Ditiocarb; D007501:Iron; D019001:Nitric Oxide Synthase