顶盖前区前核痛觉调制作用的形态学探讨──HRP束路追踪和免疫细胞化学研究

MORPHOLOGICAL APPROACH TO THE MODULATORY ACTION OF ANTERIOR PRETECTAL NUCLEUS OF PAIN ─HRP TRACING AND IMMUNOCYTOCHEMICAL STUDIES

应用ＨＲＰ束路追踪和免疫细胞化学技术研究了顶盖前区前核（ＡＰｔＮ）和中脑深部网状核（ＤｐＭｅ）之间的纤维联系以及ＡＰｔＮ内几种神经活性物质的分布。将ＨＲＰ注入ＤｐＭｅ后，发现在ＡＰｔＮ内有ＨＲＰ标记的神经元胞体和纤维终末，表明ＡＰｔＶ和ＤｐＭｅ之间存在着双向纤维联系。ＡＰｔＮ内的ＨＲＰ标记细胞呈背、腹两群的极性分布模式。背侧群标记细胞偏向ＡＰｔＮ吻段分布，其中有相当一部分ＨＲＰ标记细胞也是谷氨酸（Ｇｌｕ）阳性细胞，提示ＡＰｔＮ内的这群细胞向ＤｐＭｅ的投射纤维终末以释放Ｇｌｕ为主。ＡＰｔＮ内的ＨＲＰ标记纤维主要位于ＡＰｔＮ尾段的背外侧和腹侧，提示由ＤｐＭｅ到ＡＰｔＮ的传入纤维可能通过ＡＰｔＮ的背外侧和腹侧两条通路进入ＡＰｔＮ。免疫细胞化学染色显示，ＡＰｔＮ含有Ｇｌｕ、亮－脑啡肽（Ｌ－ＥＮＫ）、Ｐ物质（ＳＰ）、酪氨酸羟化酶（ＴＨ）和５－羟色胺（５－ＨＴ）免疫反应阳性胞体和／或纤维，但没有发现加压素（ＶＰ）和β－内啡肽（β－ＥＮＤ）阳性反应结构。上述阳性反应物质在ＡＰｔＮ内各有自己的分布模式，但并不以哪种活性物质为主，提示ＡＰｔＮ功能的多样性和复杂性。

Fiber connection between the anterior pretectal nucleus(APtN) and deep mesencephalic nucleus(DpMe)and the distributions of several neuroactive substances in the APtN were investigated by the combination of HRP tracing and immunocytochemical techniques. Following injecttion af HRP into the DpMe ,labeled fiber terminals and neuronal bodies were found in the APtN,suggesting there exist reciprocal connections between the APtN and the DpMe.The retrograde labeled cells in the APtN exhibited dorsal and ventral polar distribution patterns.The labelled cells of the former were principally located within the rostral part of the APtN, a substantial number of which were also glutamate immunoreaction positive. These indicate that APtN neurons projecting to the DpMemight excite DpMe neurons by releasing the excitatory transmitter glutamate.The findings that HRP labeled fiber terminals were mainly located in thedorsolateral and ventral parts of the caudal level of the APtN suggested that afferent fibers from the DpMe entered into the APtN through two pathways: the dorsolateral route and the ventral route.Immunocytochemical staining results indicated there exist glutamate, leucine-enkephalin ,substance P,tyrosine hydroxylase and serotonin immunoreactive cell bodies and/or fibers, but not vasopressin and β-endorphine in the APtN.The existence of these neuroactive substances, no one of which was predominant in distribution patterns, implied diversity and complexity of APtN functions.