Fishell G, van der Kooy D
Neurobiology Research Group, Department of Anatomy, University of Toronto, Ont., Canada.
Brain Res Dev Brain Res. 1989 Feb 1;45(2):239-55. doi: 10.1016/0165-3806(89)90042-4.
The mammalian striatum (the major subcortical structure in the telencephalon) can be divided into two compartments, the patch and the matrix, on the basis of various neurochemical and hodological markers expressed in the adult. The primary efferent target of striatal neurons is the substantia nigra. We have previously shown that the patch compartment sends projections to the substantia nigra embryonically; whereas the matrix does not form a similar projection until the early postnatal period (Fishell and van der Kooy, J. Neurosci., 7 (1987) 1969-1978). The projection of patch neurons to the substantia nigra is the earliest developmental marker for the patch compartment. Here we ask about the early distribution of patch projections and their possible relation to striatal compartmentalization. Embryonic anterograde axonal tracing of the striatonigral pathway can take advantage of the temporal separation of patch versus matrix projections to reveal the terminal distribution of patch striatonigral neurons independent of the nigral terminal distribution from the striatal matrix. The anterograde tracer rhodamine isothiocyanate was shown in a model system to persist in labeled neurons for more than a week, but to be available for uptake into these neurons for a few days after injection at the most. These properties of rhodamine isothiocyanate were combined experimentally with short and long term survival periods. This allowed assessment of the changing developmental distribution of nigral fibers from specifically the striatal patch compartment. In all experimental cases the anterogradely labeled sections of the substantia nigra were also stained with antibodies to tyrosine hydroxylase, which permitted differentiation of the dopamine cell rich pars compacta from the dopamine cell poor pars reticulata. The results show that in the adult the majority of patch and matrix striatonigral projections are confined to the substantia nigra pars reticulata. Furthermore, their fiber distribution within the pars reticulata is overlapping rather than complementary. Most interestingly, in the late embryonic period (most noticeably at embryonic day 19) there is a marked overlap between patch striatonigral fibers and nigral dopamine perikarya. By early postnatal times, when the matrix compartment begins to form its striatonigral projection, the overlap of patch striatonigral fibers and dopamine cells has largely disappeared. The results suggest that a transient interaction between patch striatonigral fibers and dopamine neurons (which is concomitant with the formation of striatal compartments), may be an important developmental event in the phenotypic maturation of striatal pa
哺乳动物的纹状体（端脑中主要的皮质下结构）可根据成体中表达的各种神经化学和神经通路标记物分为两个区室，即斑块区和基质区。纹状体神经元的主要传出靶点是黑质。我们之前已经表明，斑块区室在胚胎期就向黑质发出投射；而基质区直到出生后早期才形成类似的投射（菲舍尔和范德库伊，《神经科学杂志》，7 (1987) 1969 - 1978）。斑块神经元向黑质的投射是斑块区室最早的发育标记。在此，我们探讨斑块投射的早期分布及其与纹状体分区的可能关系。纹状体 - 黑质通路的胚胎期顺行轴突追踪可以利用斑块与基质投射的时间差异，来揭示斑块纹状体 - 黑质神经元的终末分布，而不依赖于来自纹状体基质的黑质终末分布。在一个模型系统中显示，顺行示踪剂异硫氰酸罗丹明在标记的神经元中持续存在超过一周，但在注射后最多几天内可被这些神经元摄取。异硫氰酸罗丹明的这些特性通过实验与短期和长期存活期相结合。这使得能够评估特别是来自纹状体斑块区室的黑质纤维不断变化的发育分布。在所有实验情况下，黑质的顺行标记切片也用酪氨酸羟化酶抗体染色，这使得富含多巴胺细胞的致密部与多巴胺细胞较少的网状部得以区分。结果表明，在成体中，大多数斑块和基质纹状体 - 黑质投射局限于黑质网状部。此外，它们在网状部内的纤维分布是重叠的而非互补的。最有趣的是，在胚胎后期（最明显的是在胚胎第19天），斑块纹状体 - 黑质纤维与黑质多巴胺神经元胞体之间存在明显的重叠。到出生后早期，当基质区室开始形成其纹状体 - 黑质投射时，斑块纹状体 - 黑质纤维与多巴胺细胞之间的重叠已基本消失。结果表明，斑块纹状体 - 黑质纤维与多巴胺神经元之间的短暂相互作用（这与纹状体区室的形成同时发生），可能是纹状体神经元表型成熟过程中的一个重要发育事件。
