Lack of anticholinergic effect of N(G)-nitro-L-arginine methylester in the small intestine.
The nitric oxide (NO)-synthase inhibitor, N(G)-nitro-L-arginine methylester (L-NAME), has been reported to have an atropine-like action. We compared the effects of L-NAME (1 mM) and atropine on isolated small intestinal preparations of the guinea-pig, rat, rabbit and mouse. Half-maximal longitudinal contractions in response to acetylcholine (50-100 nM) were not influenced by L-NAME, but were strongly suppressed by atropine (1 nM). Cholinergic 'twitch' contractions of the guinea-pig ileum were slightly enhanced by L-NAME; this effect was prevented by pretreatment with N(G)-nitro-L-arginine (L-NOARG, 100 microM), another NO synthase inhibitor. 'Twitch' contractions were concentration dependently inhibited by atropine (1-100 nM). We conclude that L-NAME is free of atropine-like activity in isolated intestinal preparations.
Barthó
L
L
Department of Pharmacology and Pharmacotherapy, University Medical School of Pécs, Hungary. lbartho@apacs.pote.hu
Horváth
G
G
Lénárd
L
L
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001285:Atropine / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005260:Female; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D019335:Nitroarginine / Q000494:pharmacology; D011817:Rabbits; D051381:Rats; D017208:Rats, Wistar
D004791:Enzyme Inhibitors; D019335:Nitroarginine; D001285:Atropine; D019001:Nitric Oxide Synthase; D000109:Acetylcholine; D019331:NG-Nitroarginine Methyl Ester