Sternini C, De Giorgio R, Furness J B
Department of Medicine, UCLA School of Medicine.
Regul Pept. 1992 Nov 20;42(1-2):15-26. doi: 10.1016/0167-0115(92)90020-u.
The pattern of nerve cells and fibers containing calcitonin gene-related peptide immunoreactivity (CGRP-IR) was investigated in the canine digestive tract by means of immunohistochemistry. CGRP-IR nerve fibers innervate all the layers of the gut, including the vasculature, with different densities depending on the region. CGRP-IR processes are sparse in the esophagus and stomach, where they are mostly confined to the enteric plexuses and vasculature. CGRP-IR fibers are quite abundant in the small and large intestine, where they form dense arborizations in the mucosa, and are numerous in the muscularis mucosae, deep muscular plexus and circular muscle. The myenteric and submucous plexuses of the intestine contain dense networks of CGRP-IR fibers and numerous CGRP-IR ganglion cells. On the other hand, in the enteric ganglia of the esophagus and stomach, in the intrapancreatic ganglia and in the ganglionated plexus of the gallbladder, CGRP-IR is restricted to non-varicose processes. A moderate density of CGRP-IR fibers supplies the endocrine and exocrine pancreas, and the fibromuscular layer and lamina propria of the gallbladder. The density of CGRP innervation in different regions can be summarized as follows: intestine >> pancreas and gallbladder > or = antrum > cardia > gastric corpus and distal esophagus. CGRP- and tachykinin (TK)-IRs are colocalized in a substantial population of fibers, particularly those distributed to the mucosa, muscularis mucosae and vasculature, whereas there was no evidence of colocalization in intrinsic ganglion cells. The present results suggest that (1) the CGRP innervation of the dog digestive system includes an intrinsic and an extrinsic component, and (2) CGRP- and TK-IRs are co-expressed in extrinsic nerve fibers. These findings extend previous observations in rats and guinea pigs and provide insights into the sites of action of CGRP in the digestive system of the dog, which has served as a model for CGRP functional studies.
采用免疫组织化学方法，研究了犬消化道中含有降钙素基因相关肽免疫反应性（CGRP-IR）的神经细胞和纤维的分布模式。CGRP-IR神经纤维支配肠道的所有层次，包括脉管系统，其密度因区域而异。CGRP-IR神经突起在食管和胃中稀疏，主要局限于肠神经丛和脉管系统。CGRP-IR纤维在小肠和大肠中相当丰富，在黏膜中形成密集的分支，并在黏膜肌层、深部肌丛和环行肌中大量存在。肠肌间神经丛和黏膜下神经丛含有密集的CGRP-IR纤维网络和大量CGRP-IR神经节细胞。另一方面，在食管和胃的肠神经节、胰腺内神经节以及胆囊的神经节丛中，CGRP-IR仅限于无曲张的神经突起。中等密度的CGRP-IR纤维供应内分泌和外分泌胰腺以及胆囊的纤维肌层和固有层。不同区域CGRP神经支配的密度可总结如下：肠道>>胰腺和胆囊>或=胃窦>贲门>胃体和食管远端。CGRP和速激肽（TK）-IR在大量纤维中共定位，特别是那些分布于黏膜、黏膜肌层和脉管系统的纤维，而在内脏神经节细胞中没有共定位的证据。目前的结果表明：（1）犬消化系统的CGRP神经支配包括内在和外在成分；（2）CGRP和TK-IR在外周神经纤维中共表达。这些发现扩展了先前在大鼠和豚鼠中的观察结果，并为CGRP在犬消化系统中的作用位点提供了见解，犬已作为CGRP功能研究的模型。
