Musings on the wanderer: What's new in our understanding of vago-vagal reflexes? I. Morphology and topography of vagal afferents innervating the GI tract
Musings on the wanderer: What's new in our understanding of vago-vagal reflexes? I. Morphology and topography of vagal afferents innervating the GI tract
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DOI：
10.1152/ajpgi.00249.2002
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发表时间：
2002-12-01
影响因子：
4.5
通讯作者：
Phillips, RJ
中科院分区：
文献类型：
--
作者：
Powley, TL;Phillips, RJ
要了解迷走-迷走神经反射的启动机制，就需要了解迷走神经传入的传导机制。这些信息假定了解受体的形态和位置。最近的解剖学研究已经确定了两种类型的迷走神经传入，这两种类型的机械感受器都分布在胃肠道(GI)的平滑肌上。这两种受体是高度专门化的，因为它们1)在形态上是不同的，2)具有不同的平滑肌靶点，3)与不同的辅助细胞形成复合体，以及4)它们在整个胃肠道的区域分布不同。相比之下，关于其他类型的迷走神经传入，特别是化学感受器的结构和区域分布的信息才刚刚开始积累。然而，这两种机械感受器的研究进展阐明了一般原理，并描述了可能适用于迷走神经传入的其他亚模式的实验问题。根据对这两种肌末梢的形态和生理观察，可以合理地假设，迷走神经受体的其他类别在形态上也是不同的，它们在结构、辅助细胞、区域分布和其他特征上存在差异。要全面了解迷走神经反射，需要对胃肠道内迷走神经受体的每一种类型进行彻底的结构和区域分析。
An understanding of the events initiating vago-vagal reflexes requires knowledge of mechanisms of transduction by vagal afferents. Such information presumes an understanding of receptor morphology and location. Anatomic studies have recently characterized two types of vagal afferents, both putative mechanoreceptors distributed in gastrointestinal (GI) smooth muscle. These two receptors are highly specialized in that they 1) are morphologically distinct, 2) have different smooth muscle targets, 3) form complexes with dissimilar accessory cells, and 4) vary in their regional distributions throughout the GI tract. By comparison, information on the architecture and regional distributions of other classes of vagal afferents, notably chemoreceptors, has only begun to accumulate. Progress on the study of the two mechanoreceptors, however, illustrates general principles and delineates experimental issues that may apply to other submodalities of vagal afferents. By extension from morphological and physiological observations on the two species of smooth muscle endings, it is reasonable to hypothesize that additional classes of vagal receptors are also differentiated morphologically and that they vary in structure, accessory cells, regional distributions, and other features. A full appreciation of vago-vagal reflexes will require thorough structural and regional analyses of each of the types of vagal receptors within the GI tract.