Boeckxstaens G E, Pelckmans P A, Bult H, De Man J G, Herman A G, van Maercke Y M
Division of Gastroenterology, Faculty of Medicine, University of Antwerp, Antwerp-Wilrijk, Belgium.
Br J Pharmacol. 1991 Feb;102(2):434-8. doi: 10.1111/j.1476-5381.1991.tb12191.x.
1 The effects of haemoglobin, and the nitric oxide (NO) biosynthesis-inhibitors NG-monomethyl-L-arginine (L-NMMA), its enantiomer D-NMMA, and NG-nitro-L-arginine (L-NNA) were investigated on nonadrenergic non-cholinergic (NANC)-mediated relaxation of circular muscle strips of the canine terminal ileum and ileocolonic junction induced by electrical stimulation, adenosine 5'-triphosphate (ATP), gamma-aminobutyric acid (GABA) and NO. 2 Tetrodotoxin, L-NMMA and L-NNA, but not D-NMMA, inhibited the relaxations induced by electrical stimulation, ATP and GABA, but not those in response to NO. 3 The inhibitory effect of L-NMMA and L-NNA was prevented by L-arginine, but not by D-arginine. L-Arginine did not potentiate any of the NANC relaxations. 4 Haemoglobin reduced the relaxation induced by electrical stimulation, ATP and GABA, and abolished those in response to NO. 5 Our results demonstrate that the ATP- and GABA-induced relaxations resulting from stimulation of intramural NANC neurones, in addition to those induced by electrical impulses, are mediated by NO or a NO releasing substance and thus provide further evidence in support of the proposal that NO is the final inhibitory NANC neurotransmitter in the canine terminal ileum and ileocolonic junction.
1 研究了血红蛋白以及一氧化氮（NO）生物合成抑制剂Nω-甲基-L-精氨酸（L-NMMA）、其对映体D-NMMA和Nω-硝基-L-精氨酸（L-NNA）对电刺激、腺苷5'-三磷酸（ATP）、γ-氨基丁酸（GABA）和NO诱导的犬回肠末端和回结肠连接处环形肌条非肾上腺素能非胆碱能（NANC）介导的舒张作用。2 河豚毒素、L-NMMA和L-NNA可抑制电刺激、ATP和GABA诱导的舒张，但不抑制对NO的舒张反应，而D-NMMA则无此作用。3 L-精氨酸可拮抗L-NMMA和L-NNA的抑制作用，而D-精氨酸则不能。L-精氨酸不能增强任何NANC介导的舒张作用。4 血红蛋白可降低电刺激、ATP和GABA诱导的舒张，并消除对NO的舒张反应。5 我们的结果表明，除电冲动诱导的舒张外，壁内NANC神经元受刺激后由ATP和GABA诱导的舒张是由NO或一种释放NO的物质介导的，从而为NO是犬回肠末端和回结肠连接处最终的抑制性NANC神经递质这一观点提供了进一步的证据。
