Inagaki H, Bishop A E, Escrig C, Wharton J, Allen-Mersh T G, Polak J M
Department of Histochemistry, Royal Postgraduate Medical School, Hammersmith Hospital, London, England.
Gastroenterology. 1991 Jul;101(1):47-54. doi: 10.1016/0016-5085(91)90458-w.
The potent vasoconstrictor endothelin was originally isolated from vascular endothelial cells but has since been found in several other tissues. The aim of this study was to establish whether endothelinlike immunoreactivity occurs in human enteric nerves and to identify endothelin binding sites using immunocytochemical and in vitro autoradiographic techniques. Endothelinlike immunoreactivity was localized to nerve bundles throughout the colon and to most of the ganglion cells of the two major plexuses, many of which costored vasoactive intestinal polypeptide. High-affinity (dissociation constant = 0.35 +/- 0.014 nmol/L; mean +/- SEM) binding sites for endothelin 1, with an apparent binding capacity of 92 +/- 6.3 amol/mm2 (mean +/- SEM), were demonstrated in the myenteric plexus, with less dense binding being found in the submucous plexus, mucosa, muscle layers, and blood vessel walls. Competition data suggested two populations of binding sites, both showing high affinities for endothelins 1 and 2, vasoactive intestinal constrictor, and sarafatoxin b but differentiated by their affinity for endothelin 3 and sarafatoxin c. This study provides evidence that endothelin is a neuropeptide in the human intestine with binding sites on neural plexuses and mucosa, suggesting a role in the modulation of intestinal motility and secretion.
强效血管收缩剂内皮素最初是从血管内皮细胞中分离出来的，但后来在其他几种组织中也被发现。本研究的目的是确定人肠神经中是否存在内皮素样免疫反应性，并使用免疫细胞化学和体外放射自显影技术鉴定内皮素结合位点。内皮素样免疫反应性定位于整个结肠的神经束以及两个主要神经丛的大多数神经节细胞，其中许多还共同储存血管活性肠多肽。在肌间神经丛中证实了内皮素1的高亲和力（解离常数=0.35±0.014 nmol/L；平均值±标准误）结合位点，其表观结合容量为92±6.3 amol/mm2（平均值±标准误），在黏膜下神经丛、黏膜、肌层和血管壁中发现的结合密度较低。竞争数据表明存在两类结合位点，两者对内皮素1和2、血管活性肠收缩剂和沙雷肽毒素b均表现出高亲和力，但对内皮素3和沙雷肽毒素c的亲和力不同。本研究提供了证据，表明内皮素是人类肠道中的一种神经肽，在神经丛和黏膜上具有结合位点，提示其在调节肠道运动和分泌中发挥作用。
