Hirafuji M, Ogawa T, Kato K, Hamaue N, Endo T, Parvez H, Minami M
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido 061-0293, Japan.
Eur J Pharmacol. 2001 Dec 7;432(2-3):149-52. doi: 10.1016/s0014-2999(01)01474-1.
The effect of noradrenaline on 5-hydroxytryptamine (5-HT) release from isolated mouse ileal tissues was investigated. Noradrenaline, but not isoprenaline, at 1 microM stimulated 5-HT release, an effect which was inhibited by yohimbine, an alpha(2)-adrenoceptor antagonist, but not by bunazosin, an alpha(1)-adrenoceptor antagonist. alpha(2)-Adrenoceptor agonists, UK 14,304 (5-bromo-6-(2-imidazolin-2-yl-amino)-quinoxaline) and clonidine at a higher concentration (10 microM) also stimulated 5-HT release, while alpha(1)-adrenoceptor agonists, methoxamine and phenylephrine, had no effect. The effect of noradrenaline was completely abolished in ileal tissues isolated from mouse treated with pertussis toxin (100 microg/kg, i.v.) for 2 days. These results suggest that noradrenaline causes 5-HT release from enterochromaffin cells in mouse ileal tissues via alpha(2)-adrenoceptor subtypes coupled to a pertussis toxin-sensitive G protein.
研究了去甲肾上腺素对分离的小鼠回肠组织中5-羟色胺（5-HT）释放的影响。1微摩尔浓度的去甲肾上腺素而非异丙肾上腺素刺激了5-HT的释放，这种作用被α(2)-肾上腺素能受体拮抗剂育亨宾抑制，但未被α(1)-肾上腺素能受体拮抗剂布那唑嗪抑制。α(2)-肾上腺素能受体激动剂UK 14,304（5-溴-6-(2-咪唑啉-2-基-氨基)-喹喔啉）和较高浓度（10微摩尔）的可乐定也刺激了5-HT的释放，而α(1)-肾上腺素能受体激动剂甲氧明和去氧肾上腺素则无此作用。在用百日咳毒素（100微克/千克，静脉注射）处理2天的小鼠分离的回肠组织中，去甲肾上腺素的作用完全消失。这些结果表明，去甲肾上腺素通过与百日咳毒素敏感的G蛋白偶联的α(2)-肾上腺素能受体亚型导致小鼠回肠组织中肠嗜铬细胞释放5-HT。
