EPR detection of endogenous nitric oxide in postischemic heart using lipid and aqueous-soluble dithiocarbamate-iron complexes.
Spin-trapping techniques combined with electron paramagnetic resonance (EPR) spectroscopy to measure nitric oxide (NO) production were compared in the ischemic-reperfused myocardium for the first time, using both aqueous-soluble and lipophilic complexes of reduced iron (Fe) with dithiocarbamate derivatives. The aqueous-soluble complex of Fe and N-methyl-D-glucamine dithiocarbamate (MGD) formed MGD2-Fe-NO complex with a characteristic triplet EPR signal (aN 12.5 G and giso = 2.04) at room temperature, in native isolated rat hearts following 40 min global ischemia and 15 min reperfusion. Diethyldithiocarbamate (DETC) and Fe formed in ischemic-reperfused myocardium the lipophilic DETC2-Fe-NO complex exhibiting an EPR signal (g perpendicular = 2.04 and g parallel = 2.02 at 77 K) with a triplet hyperfine structure at g perpendicular. Dithiocarbamate-Fe-NO complexes detected by both trapping agents were abolished by the .NO synthase inhibitor, NG-nitro-L-arginine methyl ester. Quantitatively, both trapping procedures provided similar values for tissue .NO production, which were observed primarily during ischemia. Postischemic hemodynamic recovery of the heart was not affected by the trapping procedure.
Komarov
A M
AM
Departments of Medicine and Physiology, George Washington University Medical Center, Washington, D.C. 20037, USA.
Kramer
J H
JH
Mak
I T
IT
Weglicki
W B
WB
D000818:Animals; D002614:Chelating Agents / Q000378:metabolism / Q000494:pharmacology; D004050:Ditiocarb / Q000378:metabolism / Q000494:pharmacology; D004578:Electron Spin Resonance Spectroscopy; D004791:Enzyme Inhibitors / Q000378:metabolism / Q000494:pharmacology; D005296:Ferrous Compounds / Q000378:metabolism / Q000494:pharmacology; D066298:In Vitro Techniques; D015428:Myocardial Reperfusion Injury / Q000378:metabolism*; D019331:NG-Nitroarginine Methyl Ester / Q000378:metabolism / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013012:Sorbitol / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D013113:Spin Labels; D019097:Spin Trapping; D013859:Thiocarbamates / Q000378:metabolism / Q000494:pharmacology
D002614:Chelating Agents; D004791:Enzyme Inhibitors; D005296:Ferrous Compounds; D013113:Spin Labels; D013859:Thiocarbamates; D009569:Nitric Oxide; D013012:Sorbitol; C041262:N-methyl-D-glucamine dithiocarbamate; D004050:Ditiocarb; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester