Wolf Matthias, Schrödl Falk, Neuhuber Winfried, Brehmer Axel
Institute of Anatomy I, Erlangen, Germany.
Anat Rec (Hoboken). 2007 Oct;290(10):1273-9. doi: 10.1002/ar.20577.
For years, calcitonin gene-related peptide (CGRP) has been used as a marker peptide for Dogiel type II neurons, putative intrinsic primary afferent neurons, in the pig enteric nervous system. Recently, some studies showed CGRP-positive neurons displaying distinctly different shapes. The aims of this study were to evaluate (1) the proportion of myenteric type II neurons that contain CGRP and (2) the proportion of myenteric CGRP-positive neurons that display type II vs. non-type II morphologies and to conclude if this peptide could be suited as a marker for type II neurons. For this purpose, nine myenteric whole-mounts (each one from duodenum, jejunum, and ileum, respectively, derived from three pigs) were triple-immunostained for CGRP, neurofilaments (NF), and choline acetyl transferase (ChAT). Each whole-mount was evaluated twice. First, 50 NF-stained type II neurons were selected randomly and their coreactivities for CGRP and ChAT were observed. Second, 50 CGRP-positive neurons were located randomly and their NF morphology and ChAT coreactivity were observed. Altogether, 92% of all type II neurons investigated displayed CGRP immunoreactivity, whereas 94.9% of all CGRP-reactive neurons recorded displayed type II morphology. We observed three further shapes of CGRP-positive neurons: 7 type V neurons (all were ChAT-positive; mainly in the ileal whole-mounts), 6 type I-like neurons (all were ChAT-positive), and 14 type III-like neurons (mostly ChAT-negative; mainly in duodenal and jejunal specimens). We conclude that CGRP-antibodies can be used as markers for type II neurons in the pig small intestinal myenteric plexus in quantitative studies but it should be kept in mind that up to one-tenth of CGRP-reactive neurons may be non-type II neurons. In case of single cell evaluation, CGRP-immunoreactivity alone is not suited as a marker. In such cases additional, morphological analysis is necessary.
多年来，降钙素基因相关肽（CGRP）一直被用作猪肠道神经系统中第II型Dogiel神经元（即假定的内在初级传入神经元）的标记肽。最近，一些研究表明CGRP阳性神经元呈现出明显不同的形态。本研究的目的是评估：（1）含有CGRP的肌间神经丛第II型神经元的比例；（2）呈现第II型与非第II型形态的肌间神经丛CGRP阳性神经元的比例，并判断该肽是否适合作为第II型神经元标记物。为此，对九个肌间神经丛整装标本（分别取自三只猪的十二指肠、空肠和回肠，各一个）进行了CGRP、神经丝（NF）和胆碱乙酰转移酶（ChAT）的三重免疫染色。每个整装标本评估两次。首先，随机选择50个NF染色的第II型神经元，观察其CGRP和ChAT的核心活性。其次，随机定位50个CGRP阳性神经元，观察其NF形态和ChAT核心活性。总共，所研究的所有第II型神经元中有92%显示CGRP免疫反应性，而记录的所有CGRP反应性神经元中有94.9%呈现第II型形态。我们还观察到CGRP阳性神经元的另外三种形态：7个第V型神经元（均为ChAT阳性；主要在回肠整装标本中）、6个第I型样神经元（均为ChAT阳性）和14个第III型样神经元（大多为ChAT阴性；主要在十二指肠和空肠标本中）。我们得出结论，在定量研究中，CGRP抗体可作为猪小肠肌间神经丛中第II型神经元的标记物，但应记住，高达十分之一的CGRP反应性神经元可能是非第II型神经元。在单细胞评估中，仅CGRP免疫反应性不适合作为标记物。在这种情况下，需要进行额外的形态学分析。
