Lewis D A, Morrison J H
Department of Psychiatry, University of Pittsburgh, Pennsylvania 15213.
J Comp Neurol. 1989 Apr 15;282(3):317-30. doi: 10.1002/cne.902820302.
Norepinephrine has been implicated in the regulation of a number of cortical functions, yet relatively little is known about the anatomical organization of noradrenergic axons in the expanded and highly differentiated prefrontal cortex of primates. In this study, the distribution of fibers containing dopamine-beta-hydroxylase (DBH), the enzyme that converts dopamine to norepinephrine, was characterized immunohistochemically in the prefrontal cortical regions of Old World cynomolgus monkeys (Macaca fascicularis) and New World squirrel monkeys (Saimiri sciureus). In both species, differences in the density of DBH-labeled fibers were detected both across and within many prefrontal cytoarchitectonic regions. In cynomolgus monkeys, area 8B had the greatest density of DBH-immunoreactive fibers; within this region, the medial surface had a greater density of labeled processes than the dorsal surface. Areas 9 and 24 also had a high density of DBH-labeled fibers, areas 11, 12, 13 and 25 were of intermediate density, and portions of areas 10 and 46 had the lowest density of immunoreactive fibers. Regional differences in the density of DBH-immunoreactive fibers were also present in squirrel monkey prefrontal cortex. Despite the regional variations in the density of DBH-immunoreactive fibers, the laminar distribution of these fibers was very similar across cytoarchitectonic areas of cynomolgus prefrontal cortex. Layer I contained a low density of labeled fibers which were primarily tangential in orientation. The predominantly radially oriented fibers in layers II-IV were slightly higher in density. The density of both radially and tangentially oriented immunoreactive fibers increased substantially in layer V. Fiber density decreased in layer VI; a band of tangentially oriented fibers was present in the deep portion of this layer. With a few exceptions, the laminar distribution of DBH-immunoreactive fibers in the prefrontal regions of squirrel monkey cortex was similar to that of cynomolgus monkey. Since other data suggest that anti-DBH selectively labels noradrenergic axons in monkey neocortex, the distinctive innervation patterns exhibited by DBH-immunoreactive fibers reveal the regions and layers that may be the principal sites of action of norepinephrine in exerting its effects on prefrontal cortical function.
去甲肾上腺素与多种皮质功能的调节有关，然而，对于灵长类动物扩展且高度分化的前额叶皮质中去甲肾上腺素能轴突的解剖组织，人们了解得相对较少。在本研究中，通过免疫组织化学方法对旧世界食蟹猴（猕猴）和新世界松鼠猴前额叶皮质区域中含多巴胺-β-羟化酶（DBH，将多巴胺转化为去甲肾上腺素的酶）的纤维分布进行了表征。在这两个物种中，在许多前额叶细胞构筑区域内和区域间均检测到DBH标记纤维密度的差异。在食蟹猴中，8B区的DBH免疫反应性纤维密度最高；在该区域内，内侧表面的标记突起密度高于背侧表面。9区和24区也有高密度的DBH标记纤维，11区、12区、13区和25区密度中等，10区和46区部分区域的免疫反应性纤维密度最低。松鼠猴前额叶皮质中也存在DBH免疫反应性纤维密度的区域差异。尽管DBH免疫反应性纤维密度存在区域差异，但这些纤维在食蟹猴前额叶皮质各细胞构筑区域的层状分布非常相似。I层含有低密度的标记纤维，其主要呈切线方向排列。II-IV层中主要呈放射状排列的纤维密度略高。V层中放射状和切线方向排列的免疫反应性纤维密度均大幅增加。VI层纤维密度降低；在该层深部存在一条切线方向排列的纤维带。除少数例外，松鼠猴皮质前额叶区域中DBH免疫反应性纤维的层状分布与食蟹猴相似。由于其他数据表明抗DBH可选择性标记猴新皮质中的去甲肾上腺素能轴突，DBH免疫反应性纤维所呈现的独特神经支配模式揭示了去甲肾上腺素在发挥其对前额叶皮质功能影响时可能的主要作用部位的区域和层。
