Immunocytochemical localization of substance P in the spinal trigeminal nucleus of the rat: a light and electron microscopic study.
Immunocytochemical localization of substance P in the spinal trigeminal nucleus of the rat: a light and electron microscopic study.
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发表时间：
1982
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通讯作者：
J. Priestley;P. Somogyi;A. Cuello
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作者：
J. Priestley;P. Somogyi;A. Cuello
神经肽P物质是终止于胶状质的某些初级传入纤维的候选递质。本文用免疫细胞化学方法对大鼠三叉神经脊束核胶状质内P物质进行了光镜和电镜定位研究。P物质免疫反应纤维主要位于第一层和第二层外层。超微结构分析显示，免疫反应在无髓纤维和轴突终端，其中包含agranular球形囊泡和大致密核心囊泡，主要是简单的不对称轴树突触接触。免疫反应性终端很少形成的突触肾小球的中央终端，只有在一个例子是一个染色的终端可能突触后未染色的终端。大多数突触位于外板层II的小树突上，在某些情况下，这些树突本身与其他树突形成突触前。免疫反应终末还与I、II层边缘的大神经元的索马体和近端树突形成突触。结果表明，至少有两个不同的目标，P物质的免疫反应终末在胶状质，即大板层I神经元和板层II可能的中间神经元。前者中的一些可能是投射神经元，而后者中的一些可能对应于Gobel及其同事在猫中描述的抑制性胰岛细胞。此外，结果表明，很少有P物质免疫反应性末梢接受轴-轴突触，而不是强调突触后相互作用的作用。特别是，结果表明，在P物质可能与神经肽脑啡肽突触后相互作用的几个网站。
The neuropeptide substance P is a transmitter candidate for certain primary afferent fibers which terminate in the substantia gelatinosa. In this study the light and electron microscopic localization of substance P in the substantia gelatinosa of the spinal trigeminal nucleus of the rat has been studied using immunocytochemical procedures. Substance P immunoreactive fibers were observed mainly in lamina I and outer lamina II. Ultrastructural analysis revealed immunoreactivity in unmyelinated fibers and in axon terminals which contained agranular spherical vesicles and large dense-cored vesicles and which made predominantly simple asymmetric axodendritic synaptic contacts. Immunoreactive terminals only rarely formed the central terminal of synaptic glomeruli and in only one example was a stained terminal possibly postsynaptic to an unstained terminal. The majority of synapses were onto small dendrites in outer lamina II and in some cases these dendrites were themselves presynaptic to other dendrites. Immunoreactive terminals also synapsed with the soma and proximal dendrites of large neurons on the border of laminae I and II. The results show that there are at least two distinct targets for substance P immunoreactive terminals in the substantia gelatinosa, namely the large lamina I neurons and lamina II probable interneurons. Some of the former may be projection neurons while some of the latter may correspond to the inhibitory islet cells described by Gobel and colleagues in the cat. In addition the results indicate that few substance P immunoreactive terminals receive axoaxonic synapses and emphasize instead the role of postsynaptic interactions. In particular the results suggest several sites at which substance P might interact postsynaptically with the neuropeptide enkephalin.