Inhibitory circuitry involving Y cells and Y retinal terminals in the C laminae of the cat dorsal lateral geniculate nucleus
Inhibitory circuitry involving Y cells and Y retinal terminals in the C laminae of the cat dorsal lateral geniculate nucleus
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DOI：
10.1002/cne.10640
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发表时间：
2003-06-02
影响因子：
2.5
通讯作者：
Bickford, ME
中科院分区：
文献类型：
--
作者：
Dankowski, A;Bickford, ME
我们之前确定（Datskovskaia 等人 [2001] J Comp Neurol 430:85-100），大约 40% 的 Y 视网膜末端接触猫背外侧膝状核 (dLGN) A 层的中间神经元。然而，我们没有确定 Y 视网膜末端突触后中间神经元的树突末端是否随后接触 Y 丘脑皮质细胞。为了开始解决这个问题，我们检查了 dLGN 的大细胞 C 层中 Y 视网膜末梢的突触目标，该层几乎完全由 Y 丘脑皮层细胞和中间神经元组成。我们利用之前工作中产生的材料，其中我们向上丘注射了生物素化葡聚糖胺，以回填 dLGN 中 Y 视网膜原性轴突的膝状分支。为电子显微镜准备的切片进行γ氨基丁酸（GABA）染色，以区分中间神经元和丘脑皮层细胞。我们发现，Y 视网膜轴突突触后的大部分轮廓是丘脑皮质细胞的 GABA 阴性树突（116/200，58%）。其余的是中间神经元的 GABA 阳性树突（84/200，42%），其中许多含有囊泡（F2 谱；54/200，27%）。此外，我们检查了F2图谱的突触目标，发现大细胞C层中F2图谱的几乎所有接触都发生在丘脑皮质细胞的GABA阴性树突上（199/200，99.5%）。因此，Y 视网膜原性轴突接触中间神经元，中间神经元接触 dLGN 大细胞 C 层中的 Y 丘脑皮质细胞。这表明中间神经元参与 Y 通路的调节。 (C) 2003 Wiley-Liss, Inc.
We previously established (Datskovskaia et al. [2001] J Comp Neurol 430:85-100) that roughly 40% of Y retinal terminals contact interneurons in the A lamina of the dorsal lateral geniculate nucleus (dLGN) of the cat. However, we did not establish whether the dendritic terminals of interneurons postsynaptic to Y retinal terminals subsequently contact Y thalamocortical cells. To begin to address this issue, we examined the synaptic targets of Y retinal terminals in the magnocellular C lamina of the dLGN, which is populated almost exclusively by Y thalamocortical cells and interneurons. We utilized material generated from our previous work, in which we injected the superior colliculus with biotinylated dextran amine to backfill the geniculate branches of Y retinogeniculate axons in the dLGN. Sections prepared for electron microscopy were stained for gamma aminobutyric acid (GABA) to distinguish interneurons from thalamocortical cells. We found that the majority of profiles postsynaptic to Y retinal axons were the GABA-negative dendrites of thalamocortical cells (116/200, 58%). The remainder were GABA-positive dendrites of interneurons (84/200, 42%), many of which contained vesicles (F2 profiles; 54/200, 27%). In addition, we examined the synaptic targets of F2 profiles and found that almost all contacts of F2 profiles in the magnocellular C lamina were made onto the GABA-negative dendrites of thalamocortical cells (199/200, 99.5%). Thus, Y retinogeniculate axons contact interneurons and interneurons contact Y thalamocortical cells in the magnocellular C lamina of the dLGN. This indicates that interneurons are involved in modulation of the Y pathway. (C) 2003 Wiley-Liss, Inc.