Bogers J J, Pelckmans P A, Boeckxstaens G E, De Man J G, Herman A G, Van Maercke Y M
Division of Gastroenterology, Faculty of Medicine, University of Antwerp (UIA), Belgium.
Naunyn Schmiedebergs Arch Pharmacol. 1991 Dec;344(6):716-9. doi: 10.1007/BF00174756.
The role of nitric oxide (NO) in 5-HT-induced non-adrenergic non-cholinergic (NANC) relaxations was studied on circular muscle strips of the canine ileocolonic junction (ICJ) and terminal ileum. During an acetylcholine-induced contraction, NO (10(-5) M) evoked a transient relaxation, whereas 5-HT (10(-4) M) caused an initial NANC relaxation followed by a contraction. This initial relaxation to 5-HT, but not the relaxation to NO, was significantly inhibited by the stereospecific inhibitors of the NO biosynthesis NG-monomethyl-L-arginine (L-NMMA) and NG-nitro-L-arginine (L-NNA). L-arginine, but not D-arginine, prevented the inhibitory effect of L-NMMA and L-NNA. The enantiomer of L-NMMA, D-NMMA, had no effect. Hemoglobin abolished the NO-induced relaxations and significantly inhibited the relaxation to 5-HT. From these experiments it is concluded that the 5-HT-induced NANC relaxation is mediated by NO or a NO releasing substance.
研究了一氧化氮（NO）在5-羟色胺（5-HT）诱导的犬回结肠交界（ICJ）和回肠末端环形肌条非肾上腺素能非胆碱能（NANC）舒张中的作用。在乙酰胆碱诱导的收缩过程中，NO（10⁻⁵ M）引起短暂舒张，而5-HT（10⁻⁴ M）则先引起初始NANC舒张，随后是收缩。5-HT引起的这种初始舒张，而非NO引起的舒张，被NO生物合成的立体特异性抑制剂NG-单甲基-L-精氨酸（L-NMMA）和NG-硝基-L-精氨酸（L-NNA）显著抑制。L-精氨酸，而非D-精氨酸，可防止L-NMMA和L-NNA的抑制作用。L-NMMA的对映体D-NMMA则无作用。血红蛋白消除了NO诱导的舒张，并显著抑制了对5-HT的舒张。从这些实验得出结论，5-HT诱导的NANC舒张是由NO或释放NO的物质介导的。
