纹状体中直接和间接通路中型棘突神经元的皮质和丘脑神经支配。
Cortical and thalamic innervation of direct and indirect pathway medium-sized spiny neurons in mouse striatum.
机构信息
Medical Research Council Anatomical Neuropharmacology Unit, Department of Pharmacology, University of Oxford, Oxford, OX1 3TH, UK.
出版信息
J Neurosci. 2010 Nov 3;30(44):14610-8. doi: 10.1523/JNEUROSCI.1623-10.2010.
The striatum receives major excitatory inputs from the cortex and thalamus that predominantly target the spines of medium-sized spiny neurons (MSNs). We aimed to determine whether there is any selectivity of these two excitatory afferents in their innervation of direct and indirect pathway MSNs. To address this, we used bacterial artificial chromosome transgenic mice, in which enhanced green fluorescent protein (EGFP) reports the presence of D(1) or D(2) dopamine receptor subtypes, markers of direct and indirect pathway MSNs, respectively. Excitatory afferents were identified by the selective expression of vesicular glutamate transporter type 1 (VGluT1) by corticostriatal afferents and vesicular glutamate transporter type 2 (VGluT2) by thalamostriatal afferents. A quantitative electron microscopic analysis was performed on striatal tissue from D(1) and D(2) mice that was double immunolabeled to reveal the EGFP and VGluT1 or VGluT2. We found that the proportion of synapses formed by terminals derived from the cortex and thalamus was similar for both direct and indirect pathway MSNs. Furthermore, qualitative analysis revealed that individual cortical or thalamic terminals form synapses with both direct and indirect pathway MSNs. Similarly, we observed a convergence of cortical and thalamic inputs onto individual MSNs of both direct and indirect pathway: individual EGFP-positive structures received input from both VGluT2-positive and VGluT2-negative terminals. These findings demonstrate that direct and indirect pathway MSNs are similarly innervated by cortical and thalamic afferents; both projections are thus likely to be critical in the control of MSNs and hence play fundamental roles in the expression of basal ganglia function.
纹状体从皮层和丘脑接收主要的兴奋性输入,这些输入主要靶向中型棘突神经元(MSN)的棘突。我们旨在确定这两种兴奋性传入在支配直接和间接通路 MSN 时是否具有任何选择性。为了解决这个问题,我们使用了细菌人工染色体转基因小鼠,其中增强型绿色荧光蛋白(EGFP)报告 D1 或 D2 多巴胺受体亚型的存在,分别是直接和间接通路 MSN 的标志物。兴奋性传入物通过皮层纹状体传入物的囊泡谷氨酸转运体 1(VGluT1)和丘脑纹状体传入物的囊泡谷氨酸转运体 2(VGluT2)的选择性表达来鉴定。对来自 D1 和 D2 小鼠的纹状体组织进行了定量电子显微镜分析,该组织通过双重免疫标记揭示 EGFP 和 VGluT1 或 VGluT2。我们发现,来自皮层和丘脑的末端形成的突触比例对于直接和间接通路 MSN 都是相似的。此外,定性分析表明,单个皮层或丘脑末端与直接和间接通路 MSN 形成突触。同样,我们观察到皮质和丘脑输入在直接和间接通路的单个 MSN 上汇聚:单个 EGFP 阳性结构接收来自 VGluT2 阳性和 VGluT2 阴性末端的输入。这些发现表明,直接和间接通路 MSN 被皮层和丘脑传入物同样支配;因此,这两个投射都可能在 MSN 的控制中至关重要,因此在基底神经节功能的表达中发挥着基本作用。