Burgunder J M, Young W S
Laboratory of Cell Biology, National Institute of Mental Health, Bethesda, Maryland 20892.
J Comp Neurol. 1990 Oct 1;300(1):26-46. doi: 10.1002/cne.903000104.
Recent studies of neuronal cholecystokinin (CCK) expression performed with more sensitive techniques have demonstrated that the distribution of the expression of this peptide is more widespread than previously thought. In the present study, hybridization histochemistry was used to map cortical neurons expressing the CCK gene in adult and developing rats. Retrograde tracing with Fluorogold in combination with hybridization histochemistry was used to demonstrate some of the projections of these neurons. Neurons expressing the CCK gene were found in all areas of the neo- and allocortices. They were of several morphological types, including pyramidal neurons, and were found in almost all layers, albeit at different relative numbers and with different levels of expression. Generally, layers II and III, deep layer V, and layer VI had many neurons expressing CCK mRNA. Cortical CCK expression was first detected on the 15th day of gestation in the primordial plexiform layer. Expression developed thereafter in a regular and continuous fashion until an adult-like pattern was present on the 21st day after birth. Cortical neurons containing CCK mRNA were found in almost all the projections studied. Many neurons in both neo- and allocortical areas with cortico-cortical, associational, and commissural pathways contained CCK mRNA. Similarly, numerous corticostriatal neurons contained CCK mRNA; however, only a few corticothalamic neurons expressed CCK mRNA. These results demonstrate that in the rat cortex the distribution of projection neurons expressing CCK is much more widespread than had been previously shown and will stimulate further investigations into the role of CCK in these neurons.
近期采用更灵敏技术对神经元胆囊收缩素（CCK）表达进行的研究表明，该肽的表达分布比之前认为的更为广泛。在本研究中，运用杂交组织化学方法对成年和发育中大鼠表达CCK基因的皮质神经元进行定位。将荧光金逆行追踪与杂交组织化学相结合，以显示这些神经元的一些投射。在新皮质和旧皮质的所有区域均发现了表达CCK基因的神经元。它们有几种形态类型，包括锥体神经元，几乎存在于所有层中，尽管相对数量不同且表达水平各异。一般来说，第II层和第III层、深层第V层以及第VI层有许多表达CCK mRNA的神经元。皮质CCK表达在妊娠第15天于原始丛状层首次被检测到。此后表达以规则且持续的方式发展，直至出生后第21天呈现出类似成年的模式。在所研究的几乎所有投射中都发现了含有CCK mRNA的皮质神经元。新皮质和旧皮质区域中许多具有皮质 - 皮质、联合和连合通路的神经元都含有CCK mRNA。同样，大量皮质纹状体神经元含有CCK mRNA；然而，只有少数皮质丘脑神经元表达CCK mRNA。这些结果表明，在大鼠皮质中，表达CCK的投射神经元的分布比之前所显示的要广泛得多，这将激发对CCK在这些神经元中作用的进一步研究。
