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.
Division of Bioinorganic Chemistry, Institute for Life Support Technology, Yamagata Technopolis Foundation, Matsuei, Japan.
Y
Y
Suzuki
S
S
Fujii
Y
Y
Numagami
T
T
Tominaga
T
T
Yoshimoto
T
T
Yoshimura
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