Origins of glutamatergic terminals in the inferior colliculus identified by retrograde transport and expression of VGLUT1 and VGLUT2 genes
Origins of glutamatergic terminals in the inferior colliculus identified by retrograde transport and expression of VGLUT1 and VGLUT2 genes
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DOI：
10.3389/fnana.2010.00135
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发表时间：
2010-09-28
影响因子：
2.9
通讯作者：
Oliver, Douglas L.
中科院分区：
文献类型：
--
作者：
Ito, Tetsufumi;Oliver, Douglas L.
含有囊泡谷氨酸转运体(VGLUT)2的终末在顶盖丘脑GABA能神经元上形成密集的轴体突触。这是三种转运蛋白组合所识别的下丘谷氨酸能突触之一：VGLUT1，VGLUT2，或同时存在VGLUT1和VGLUT2。为了确定这三类谷氨酸能终末的来源(S)，我们采用荧光金(FG)注入下丘，逆行运输结合VGLUT1和VGLUT2基因的原位杂交的方法。FG阳性胞体的分布与以前的报道一致。在听皮质，所有FG阳性细胞仅表达VGLUT1。在IC中，大多数FG阳性细胞仅表达VGLUT2。在外侧丘系的中间核，大多数FG阳性细胞表达VGLUT2，少数FG阳性细胞同时表达VGLUT1和VGLU2。在上橄榄复合体(SOC)，表达VGLUT2的FG阳性细胞多数位于上橄榄外侧核、上橄榄内侧核和部分橄榄周核。在耳蜗腹侧核，几乎所有FG阳性细胞都表达VGLUT1&2，而在耳蜗背侧核，绝大多数FG阳性细胞仅表达VGLUT2。结果表明：(1)VGLUT2终末最可能的来源是外侧丘系中间核、耳蜗背核、内侧和外侧上橄榄核以及IC本身；(2)IC内VGLUT1终末仅起源于同侧听皮质；(3)IC内VGLUT1和VGLUT2终末主要起源于VCN，SOC和丘脑外侧核也有少量贡献。
Terminals containing vesicular glutamate transporter (VGLUT) 2 make dense axosomatic synapses on tectothalamic GABAergic neurons. These are one of the three types of glutamatergic synapses in the inferior colliculus (IC) identified by one of three combinations of transporter protein: VGLUT1 only, VGLUT2 only, or both VGLUT1 and 2. To identify the source(s) of these three classes of glutamatergic terminals, we employed the injection of Fluorogold (FG) into the IC and retrograde transport in combination with in situ hybridization for VGLUT1 and VGLUT2 mRNA. The distribution of FG-positive soma was consistent with previous reports. In the auditory cortex, all FG-positive cells expressed only VGLUT1. In the IC, the majority of FG-positive cells expressed only VGLUT2. In the intermediate nucleus of the lateral lemniscus, most FG-positive cells expressed VGLUT2, and a few FG-positive cells expressed both VGLUT1 and 2. In the superior olivary complex (SOC), the majority of FG-positive cells expressing VGLUT2 were in the lateral superior olive, medial superior olive, and some periolivary nuclei. Fewer FG-positive cells expressed VGLUT1&2. In the ventral cochlear nucleus, almost all FG-positive cells expressed VGLUT1&2. On the other hand in the dorsal cochlear nucleus, the vast majority of FG-positive cells expressed only VGLUT2. Our data suggest that (1) the most likely sources of VGLUT2 terminals in the IC are the intermediate nucleus of the lateral lemniscus, the dorsal cochlear nucleus, the medial and lateral superior olive, and the IC itself, (2) VGLUT1 terminals in the IC originate only in the ipsilateral auditory cortex, and (3) VGLUT1&2 terminals in IC originate mainly from the VCN with minor contributions from the SOC and the lateral lemniscal nuclei.