Muscarinic M2 acetylcholine receptor distribution in the guinea-pig gastrointestinal tract
Muscarinic M2 acetylcholine receptor distribution in the guinea-pig gastrointestinal tract
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DOI：
10.1016/j.neuroscience.2005.11.021
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发表时间：
2006-01-01
期刊：
影响因子：
3.3
通讯作者：
Nojyo, Y
中科院分区：
文献类型：
--
作者：
Iino, S;Nojyo, Y
在肠神经系统中，乙酰胆碱是引起胃肠道平滑肌收缩最常见的神经递质。胆碱能信号是由平滑肌细胞表面的毒蕈碱乙酰胆碱受体介导的。已经鉴定并鉴定了5种不同的毒蕈碱受体亚型（M-1-M-5），它们都属于g蛋白偶联受体的超家族。毒蕈碱M-2乙酰胆碱受体是胃肠道平滑肌组织中表达的主要毒蕈碱受体亚型，在胃肠道中与较少的M-3受体共表达。在这项研究中，我们使用一种特异性抗体检测了豚鼠胃肠道中M-2受体的免疫组织化学分布。M-2受体样免疫反应性主要与胃肠道平滑肌细胞相关。平滑肌细胞的M-2受体样免疫反应性分布在与小泡相关的整个细胞膜上。在结肠近端，平滑肌细胞的M-2受体样免疫反应性较弱。在小肠中，具有神经激肽1受体样免疫反应性的Cajal间质细胞具有强烈的M-2受体样免疫反应性。在结肠近端，肌内和肌间质细胞Cajal表现出M-2受体样免疫反应性。这些结果表明，在胃肠道肌肉组织中，M-2受体同时分布在Cajal的平滑肌细胞和间质细胞中，提示M-2受体诱导平滑肌细胞收缩，Cajal间质细胞是肠胆碱能神经元的神经支配部位。(c) 2005 IBRO。Elsevier Ltd.出版。版权所有。
In the enteric nervous system, acetylcholine is the most common neurotransmitter to induce gastrointestinal smooth muscle contractions. Cholinergic signaling is mediated by muscarinic acetylcholine receptors on the surface of smooth muscle cells. Five different muscarinic receptor subtypes (M-1-M-5) have been identified and characterized, all of which belong to the superfamily of the G-protein-coupled receptor. The muscarinic M-2 acetylcholine receptor is the major muscarinic receptor subtype expressed by smooth muscle tissues in the gastrointestinal tract, where it is coexpressed with a smaller population of M-3 receptor. In this study, we examined the immunohistochemical distribution of the M-2 receptor using a specific antibody in the guinea-pig gastrointestinal tract. M-2 receptor-like immunoreactivity was mainly observed as associated with smooth muscle cells in the gastrointestinal tract. M-2 receptor-like immunoreactivity in smooth muscle cells was distributed throughout the cell membrane associated with caveolae. In the proximal colon, M-2 receptor-like immunoreactivity in the smooth muscle cells was weak. In the small intestine, interstitial cells of Cajal that possessed neurokinin 1 receptor-like immunoreactivity had intense M-2 receptor-like immunoreactivity. In the proximal colon, intramuscular and myenteric interstitial cells of Cajal exhibited M-2 receptor-like immunoreactivity. These findings indicate that, in the gastrointestinal musculature, M-2 receptors are distributed both in the smooth muscle cells and interstitial cells of Cajal, suggesting that the M-2 receptor elicits smooth muscle cell contraction and the interstitial cells of Cajal are the sites of innervation by enteric cholinergic neurons. (c) 2005 IBRO. Published by Elsevier Ltd. All rights reserved.