Coexpression of VGLUT1 and VGLUT2 in precerebellar neurons in the lateral reticular nucleus of the rat
Coexpression of VGLUT1 and VGLUT2 in precerebellar neurons in the lateral reticular nucleus of the rat
复制标题
VGLUT1和VGLUT2在大鼠外侧网状核小脑前神经元中的共表达
DOI：
10.1016/j.brainresbull.2020.06.008
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发表时间：
2020-09-01
影响因子：
3.8
通讯作者：
Li, Jin-Lian
中科院分区：
文献类型：
--
作者：
Li, Zhi-Hong;Zhang, Chun-Kui;Li, Jin-Lian
囊泡谷氨酸转运体(VGLUT)1和VGLUT2已被报道在大多数脑区互补分布，并被认为定义了不同的功能元件。以往的研究表明，VGLUT1和VGLUT2在外侧网状核(LRN)中表达，LRN是向小脑发送苔藓纤维的关键前核。在本研究中，我们首先用双荧光原位杂交技术检测了VGLUT1和VGLUT2在大鼠LRN中的共表达。约81.89%的谷氨酸能LRN神经元同时表达VGLUT1和VGLUT2基因，其余仅表达VGLUT1和VGLUT2基因。然后我们将逆行示踪剂荧光金(FG)注入小脑皮质，观察到FG标记的LRN神经元中分别有95.01%和86.80%的神经元表达VGLUT1和VGLUT2 mRNA。我们进一步将顺行示踪剂生物素化葡聚糖胺(BDA)注入LRN，发现小脑皮质颗粒层中约82.6%的BDA标记轴突终末同时显示VGLUT1和VGLUT2免疫阳性。随后，我们在电子显微镜下观察到，VGLUT1或VGLUT2免疫反应阳性的顺行标记轴突终末与小脑神经元的树突轮廓形成不对称突触。最后，通过病毒载体介导的siRNA转染法选择性下调VGLUT1和VGLUT2基因的表达，并检测到大鼠前肢的精细运动受到干扰。这些结果表明，共同表达VGLUT1和VGLUT2的LRN神经元投射到小脑皮质，这些神经元可能在调节前肢运动中起关键作用。
Vesicular glutamate transporter (VGLUT) 1 and VGLUT2 have been reported to distribute complementally in most brain regions and have been assumed to define distinct functional elements. Previous studies have shown the expression of VGLUT1 mRNA and VGLUT2 mRNA in the lateral reticular nucleus (LRN), a key precerebellar nucleus sending mossy fibers to the cerebellum. In the present study, we firstly examined the coexpression of VGLUT1 and VGLUT2 mRNA in the LRN of the rat by dual-fluorescence in situ hybridization. About 81.89 % of glutamatergic LRN neurons coexpressed VGLUT1 and VGLUT2 mRNA, and the others expressed either VGLUT1 or VGLUT2 mRNA. We then injected the retrograde tracer Fluogold (FG) into the vermal cortex of cerebellum, and observed that 95.01 % and 86.80 % of FG-labeled LRN neurons expressed VGLUT1 or VGLUT2 mRNA respectively. We further injected the anterograde tracer biotinylated dextran amine (BDA) into the LRN, and found about 82.6 % of BDA labeled axon terminals in the granular layer of cerebellar cortex showed both VGLUT1- and VGLUT2-immunoreactivities. Afterwards, we observed under electron microscopy that anterogradely labeled axon terminals showing immunoreactivity for VGLUT1 or VGLUT2 made asymmetric synapses with dendritic profiles of cerebellar neurons. Finally, we selectively down-regulated the expression of VGLUT1 mRNA or VGLUT2 mRNA by using viral vector mediated siRNA transfection and detected that the fine movements of the forelimb of rats were disturbed. These results indicated that LRN neurons coexpressing VGLUT1 and VGLUT2 project to the cerebellar cortex and these neurons might be critical in mediating the forelimb movements.