Prensa L, Cossette M, Parent A
Laboratoire de Neurobiologie, Centre de recherche Université Laval Robert-Giffard, 2601, de la Canardière, Local F-6500, Quebec, Beauport, Canada G1J 2G3.
J Chem Neuroanat. 2000 Dec;20(3-4):207-13. doi: 10.1016/s0891-0618(00)00099-5.
This paper summarises the results of some of our recent tyrosine hydroxylase (TH) immunohistochemical studies of the dopaminergic innervation of the human basal ganglia. It also reports new findings on the presence of TH-immunoreactive (ir) neurons in the striatum. Our data show the existence of nigrostriatal TH-ir axons that provide collaterals arborizing in the globus pallidus and subthalamic nucleus. These thin and varicose collaterals emerge from thick and smooth axons that course along the main output pathways of the basal ganglia, including the ansa lenticularis, the lenticular fasciculus and Wilson's pencils. We postulate that this extrastriatal innervation, which allows nigral dopaminergic neurons to directly affect the pallidum and subthalamic nucleus, plays a critical role in the functional organisation of human basal ganglia. The TH-ir fibres that reach the striatum arborize according to a highly heterogeneous pattern. At rostral striatal levels, numerous small TH-poor zones embedded in a TH-rich matrix correspond to calbindin-poor striosomes and calbindin-rich extrastriosomal matrix, respectively. At caudal striatal levels, in contrast, striosomes display a TH immunostaining that is more intense than that of the matrix. A significant number of small, oval, aspiny TH-ir neurons scattered throughout the rostrocaudal extent of the caudate nucleus and putamen, together with a few larger, multipolar, spiny TH-ir neurons lying principally within the ventral portion of the putamen, were disclosed in human. This potential source of intrinsic striatal dopamine might play an important role in the functional organisation of the human striatum, particularly in case of Parkinson's disease.
本文总结了我们近期对人类基底神经节多巴胺能神经支配进行的一些酪氨酸羟化酶（TH）免疫组织化学研究的结果。它还报告了纹状体中存在TH免疫反应性（ir）神经元的新发现。我们的数据显示存在黑质纹状体TH-ir轴突，这些轴突在苍白球和丘脑底核发出分支并形成树突。这些细的、有曲张的分支从沿着基底神经节主要输出通路走行的粗的、平滑的轴突发出，这些通路包括豆状袢、豆状束和威尔逊束。我们推测这种纹状体以外的神经支配，使黑质多巴胺能神经元能够直接影响苍白球和丘脑底核，在人类基底神经节的功能组织中起关键作用。到达纹状体的TH-ir纤维根据高度异质性模式形成树突。在纹状体前部水平，嵌入富含TH的基质中的许多小的TH贫乏区分别对应于富含钙结合蛋白的纹状体小体和富含钙结合蛋白的纹状体小体外部基质。相反，在纹状体后部水平，纹状体小体显示出比基质更强的TH免疫染色。在人类中发现了大量小的、椭圆形、无棘的TH-ir神经元散布在尾状核和壳核的前后范围内，以及一些主要位于壳核腹侧部分的较大的、多极的、有棘的TH-ir神经元。这种纹状体内源性多巴胺的潜在来源可能在人类纹状体的功能组织中起重要作用，特别是在帕金森病的情况下。
