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 μM), 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. Copyright (C) 1999 Elsevier Science B.V.
- Ileum, guinea-pig, rat, rabbit, mouse
- L-NAME (N(G)-nitro-L-arginine methylester)
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