Reversal of in vitro lipopolysaccharide-induced suppression of contraction in rat aorta by NG-nitro-arginine, diphenyleneiodonium and di-2-thienyliodonium.
The effects of NG-nitro-L-arginine (L-NNA), D-NNA, diphenyleneiodonium and di-2-thienyliodonium on contraction were studied in endothelium-denuded rat aortic rings incubated for 4 h with lipopolysaccharide (10 mu g ml-1) or vehicle. Lipopolysaccharide reduced Emax and increased EC50 of the phenylephrine (10-9-10-5 M) curve. Addition of D-NNA (4, 6 x 10-4 M), L-NNA (1, 10 x 10-6 M) and diphenyleneiodonium (1, 3 x 10-7 M), but not di-2-thienyliodonium (10-7 M), increased Emax and reduced EC50 of the phenylephrine curve of lipopolysaccharide-incubated but not control rings. Therefore, D-NNA, L-NNA and diphenyleneiodonium, but not di-2-thienyliodonium, inhibit inducible NO synthase in vascular smooth muscles.
Palacios
B
B
Department of Pharacology and Therapeutics, Faculty of Medicine, The University of British Columbia, Vancouver, Canada.
Cheng
X
X
Pang
C C
CC
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000037:antagonists & inhibitors; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D019335:Nitroarginine / Q000494:pharmacology*; D009861:Onium Compounds / Q000494:pharmacology*; D010656:Phenylephrine / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013876:Thiophenes / Q000494:pharmacology*
D007004:Hypoglycemic Agents; D008070:Lipopolysaccharides; D009861:Onium Compounds; D013876:Thiophenes; D010656:Phenylephrine; D019335:Nitroarginine; C051503:iodonium thiophene; C007517:diphenyleneiodonium