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Nitronyl nitroxides as probes to study the mechanism of vasodilatory action of nitrovasodilators, nitrone spin traps, and nitroxides: role of nitric oxide. Free Radic Biol Med 1995 Feb;18(2):169-77



Pubmed ID




Scopus ID

2-s2.0-0028796439   34 Citations


Nitronyl nitroxides have been used to trap nitric oxide (.NO) produced during visible irradiation of nitrovasodilators such as sodium nitroprusside (Joseph et al., Biochem. Biophys. Res. Commun. 192:926-934; 1993). We have also shown that nitrone and nitroso spin traps exert a potent vasodilatory effect in the isolated perfused rat heart (Konorev et al., Free Radic. Biol. Med. 14:127-137, 1993). The objective of this study was to investigate the effect of nitronyl nitroxides on the vasodilatory action of sodium nitroprusside (SNP), S-nitroso-N-acetylpenicillamine (SNAP), alpha-(4-pyridyl-1-oxide)-N-tert-butyl nitrone (POBN) and 4-hydroxy-2,2,6,6-tetramethylpiperidinyloxy free radical (TEMPOL) in the isolated perfused rat heart model. In this study, we have used the following nitronyl nitroxides as nitric oxide traps: 2-(p-carboxyphenyl)-4,4,5,5-tetramethyl imidazoline-3-oxide 1-oxyl (SLI) and 2(1',1'-dimethyl-2'-hydroxyethyl)-4,4,5,5-tetramethyl imidazoline-3-oxide 1-oxyl (SLII). Under in vitro conditions, both SLI and SLII trapped .NO released from SNP/light treatment and from spontaneous decomposition of SNAP, forming the corresponding imino nitroxides, which were characterized by electron spin resonance (ESR) technique. In isolated hearts, SNP (2 mumol/l) and SNAP (20 mumol/l) increased coronary flow rate to a maximum of 185% and 190%, respectively. SNP-induced vasodilation was inhibited by SLI (0.05-3 mmol/l) from 162% to 131% of baseline, and SNAP-induced vasodilation was inhibited by SLII (0.05-1.2 mmol/l) from 190% to 136% of baseline. In contrast, neither SLI nor SLII inhibited the vasodilatory action elicited by POBN or TEMPOL.(ABSTRACT TRUNCATED AT 250 WORDS)

Author List

Konorev EA, Tarpey MM, Joseph J, Baker JE, Kalyanaraman B


John E. Baker PhD Professor in the Surgery department at Medical College of Wisconsin
Balaraman Kalyanaraman PhD Chair, Professor in the Biophysics department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Coronary Circulation
Cyclic N-Oxides
Electron Spin Resonance Spectroscopy
Nitric Oxide
Nitrogen Oxides
Rats, Sprague-Dawley
Spin Labels
Vasodilator Agents
jenkins-FCD Prod-482 91ad8a360b6da540234915ea01ff80e38bfdb40a