Dopamine transporter immunoreactivity in monkey cerebral cortex: Regional, laminar, and ultrastructural localization
Dopamine transporter immunoreactivity in monkey cerebral cortex: Regional, laminar, and ultrastructural localization
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DOI：
10.1002/cne.1092
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发表时间：
2001-03-26
影响因子：
2.5
通讯作者：
Sampson, A
中科院分区：
文献类型：
--
作者：
Lewis, DA;Melchitzky, DS;Sampson, A
多巴胺（DA）影响灵长类动物大脑皮层介导的许多认知和运动功能，并且已知DA膜转运体（DAT）是啮齿类动物皮层下结构中DA神经传递的关键调节剂。为了深入了解可能的功能作用的皮质DAT，我们比较了区域，层状和超微结构分布的DAT免疫反应的酪氨酸羟化酶（TH），在DA合成的限速酶，在猕猴的大脑皮层。DAT-免疫反应（DAT-IR）轴突存在于整个皮层地幔，在密度和分层分布跨cytoarchitectonic地区的重大差异。特别地，高密度的DAT-IR轴突存在于某些区域（例如，后顶叶皮层，齿状回），以前认为没有收到大量的DA输入。DAT-IR轴突的层状分布范围从标记轴突的有限定位到轻度神经支配区域中的第1层到所有6个皮质层中的轴突的存在，在高度神经支配的区域中，在深层3中具有特别密集的神经丛。这些区域和层状模式与TH-IR轴突的模式相似，但观察到DAT的纤维形态和超微结构定位存在一些差异。例如，与TH相反，皮质中的DAT免疫反应主要定位于小直径轮廓，而在尾状核背外侧，DAT和TH免疫反应存在于大直径和小直径轮廓中，这可能分别代表静脉曲张和相互曲张的轴突段。总的来说，DAT-IR轴突的分布证实并扩展了以前的报告的结果，使用其他标记的DA轴突，即DA神经支配的灵长类动物大脑皮层是全球性的，但专门的区域基础和层状基础。特别是，这些观察结果揭示了一个直接和有效的影响DA后顶叶皮层和颞叶的某些区域的神经元活动的解剖基板。然而，由于其主要分布到小直径的配置文件，DAT的免疫反应可能不是一个合适的超微结构标记较大的DA静脉曲张在灵长类动物皮质。此外，这种分布的DAT表明，皮质DA纤维可能允许更大的神经递质扩散比皮质下DA轴突。(C)2001 Wiley-Liss，Inc.
Dopamine IDA) influences a number of cognitive and motor functions that are mediated by the primate cerebral cortex, and the DA membrane transporter (DAT) is known to be a critical regulator of DA neurotransmission in subcortical structures in rodents. To gain insight into the possible functional role of cortical DAT, we compared the regional, laminar, and ultrastructural distribution of DAT immunoreactivity to that of tyrosine hydroxylase (TH), the rate-limiting enzyme in DA synthesis, in the cerebral cortex of macaque monkeys. DAT-immunoreactive (DAT-IR) axons were present throughout the cortical mantle, with substantial differences in density and laminar distribution across cytoarchitectonic areas. In particular, high densities of DAT-IR axons were present in certain regions (e.g., posterior parietal cortex, dentate gyrus) not previously thought to receive a substantial DA input. The laminar distribution of DAT-IR axons ranged from a restricted localization of labeled axons to layer 1 in lightly innervated regions to the presence of axons in all six cortical layers, with a particularly dense plexus in deep layer 3, in highly innervated regions. These regional and laminar patterns paralleled those of TH-IR axons, but several differences in fiber morphology and ultrastructural localization of DAT were observed. For example, in contrast to TH, DAT immunoreactivity in the cortex was localized predominantly to small-diameter profiles, whereas, in the dorsolateral caudate nucleus, DAT and TH immunoreactivities were present in both large-diameter and small-diameter profiles, which may represent varicose and intervaricose axon segments, respectively. Overall, the distribution of DAT-IR axons confirms and extends the results of previous reports, using other markers of DA axons, that the DA innervation of the primate cerebral cortex is global but specialized on both a regional basis and a laminar basis. In particular, these observations reveal an anatomical substrate for a direct and potent influence of DA over neuronal activity in posterior parietal cortex and in certain regions of the temporal lobe. However, due to its predominant distribution to small-diameter profiles, immunoreactivity for DAT may not be an appropriate ultrastructural marker for larger DA varicosities in the primate cortex. Moreover, this distribution of DAT suggests that cortical DA fibers may permit greater neurotransmitter diffusion than subcortical DA axons. (C) 2001 Wiley-Liss, Inc.