Barroso-Chinea Pedro, Castle María, Aymerich María S, Lanciego José L
Area de Neurociencias, Centro de Investigación Médica Aplicada (CIMA) and Centro de Investigación en Red de Enfermedades Neurodegenerativas (CIBERNED), Facultad de Medicina, Universidad de Navarra, Spain.
J Chem Neuroanat. 2008 Jan;35(1):101-7. doi: 10.1016/j.jchemneu.2007.08.001. Epub 2007 Aug 8.
The present study is focused on the analysis of the vesicular glutamate transporters 1 and 2 (VGLUT1 and VGLUT2) used by thalamic neurons giving rise to the thalamostriatal system. Instead of studying the distribution of VGLUT proteins at the level of thalamostriatal terminals, this report is focused on identifying the expression of the VGLUT mRNAs within the parent cell bodies of thalamic neurons innervating the striatum. For this purpose, we have combined dual in situ hybridization to detect both VGLUT1 and VGLUT2 mRNAs together with retrograde tracing with cholera toxin. Our results show that VGLUT2 is the only vesicular glutamate transporter expressed in thalamostriatal-projecting neurons located in the midline and intralaminar nuclei, whereas all neurons from the ventral thalamic nuclei innervating the striatum express both VGLUTs, at least at the mRNA level. Indeed, the mRNAs encoding for VGLUT1 and VGLUT2 displayed a sharp complementary subcellular distribution within neurons from the ventral thalamic nuclei giving rise to thalamostriatal projections. The differential distribution of VGLUT mRNAs lead us to conclude that the thalamostriatal pathway is a dual system, composed by a preponderant projection arising from the midline and intralaminar nuclei using VGLUT2 as the glutamate transporter, together with another important source of striatal afferents arising from neurons in the ventral thalamic relay nuclei containing both kinds of vesicular glutamate transporters.
本研究聚焦于对丘脑神经元所使用的囊泡谷氨酸转运体1和2（VGLUT1和VGLUT2）的分析，这些丘脑神经元构成了丘脑纹状体系统。本报告并非研究VGLUT蛋白在丘脑纹状体终末水平的分布，而是着重于确定支配纹状体的丘脑神经元胞体中VGLUT mRNA的表达情况。为此，我们将用于检测VGLUT1和VGLUT2 mRNA的双重原位杂交与霍乱毒素逆行追踪相结合。我们的结果表明，VGLUT2是位于中线和板内核的丘脑纹状体投射神经元中唯一表达的囊泡谷氨酸转运体，而支配纹状体的腹侧丘脑核的所有神经元至少在mRNA水平上都表达这两种VGLUT。实际上，编码VGLUT1和VGLUT2的mRNA在产生丘脑纹状体投射的腹侧丘脑核的神经元内呈现出明显互补的亚细胞分布。VGLUT mRNA的差异分布使我们得出结论，丘脑纹状体通路是一个双重系统，由主要从中线和板内核发出的以VGLUT2作为谷氨酸转运体的投射，以及来自含有两种囊泡谷氨酸转运体的腹侧丘脑中继核神经元的另一个重要的纹状体传入源组成。
