PDF(Pubmed)
Abstract：
In the monkey retina, there are two distinct types of axon-bearing horizontal cells, known as H1 and H2 horizontal cells (HCs). In this study, cell bodies were prelabled using 4\',6-diamidino-2-phenylindole (DAPI), and both H1 and H2 horizontal cells were filled with Neurobiotin™ to reveal their coupling, cellular details, and photoreceptor contacts. The confocal analysis of H1 and H2 HCs was used to assess the colocalization of terminal dendrites with glutamate receptors at cone pedicles. After filling H1 somas, a large coupled mosaic of H1 cells was labeled. The dendritic terminals of H1 cells contacted red/green cone pedicles, with the occasional sparse contact with blue cone pedicles observed. The H2 cells were also dye-coupled. They had larger dendritic fields and lower densities. The dendritic terminals of H2 cells preferentially contacted blue cone pedicles, but additional contacts with nearly all cones within the dendritic field were still observed. The red/green cones constitute 99% of the input to H1 HCs, whereas H2 HCs receive a more balanced input, which is composed of 58% red/green cones and 42% blue cones. These observations confirm those made in earlier studies on primate horizontal cells by Dacey and Goodchild in 1996. Both H1 and H2 HCs were axon-bearing. H1 axon terminals (H1 ATs) were independently coupled and contacted rod spherules exclusively. In contrast, the H2 axon terminals contacted cones, with some preference for blue cone pedicles, as reported by Chan and Grünert in 1998. The primate retina contains three independently coupled HC networks in the outer plexiform layer (OPL), identified as H1 and H2 somatic dendrites, and H1 ATs. At each cone pedicle, the colocalization of both H1 and H2 dendritic tips with GluA4 subunits close to the cone synaptic ribbons indicates that glutamate signaling from the cones to H1 and H2 horizontal cells is mediated by α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors.
摘要：
在猴子的视网膜上,有两种不同类型的轴突水平细胞，称为H1和H2水平细胞(HCs)。在这项研究中,细胞体用4'预先标记，6-二氨基-2-苯基吲哚（DAPI），H1和H2水平细胞都充满了Neurobiotin™以揭示它们的偶联，蜂窝细节，和感光体接触。H1和H2HC的共聚焦分析用于评估末端树突与锥形蒂谷氨酸受体的共定位。填充H1SONAS后，标记了大的H1细胞偶联镶嵌。H1细胞的树突状末端接触红色/绿色视锥蒂，偶尔观察到与蓝色锥形椎弓根的稀疏接触。H2电池也是染料偶联的。他们有更大的树突场和更低的密度。H2细胞的树突状末端优先接触蓝锥蒂，但仍观察到与树突场内几乎所有视锥细胞的额外接触。红色/绿色视锥构成H1HC输入的99%，而H2HC接收更平衡的输入，它由58％的红色/绿色视锥和42％的蓝色视锥组成。这些观察结果证实了Dacey和Goodchild在1996年对灵长类水平细胞的早期研究中所做的那些观察结果。H1和H2HC均带有轴突。H1轴突末端（H1AT）独立耦合并仅与棒状球体接触。相比之下,H2轴突末端接触视锥，有些偏爱蓝色锥形椎弓根，正如Chan和Grünert在1998年报道的那样。灵长类视网膜在外部丛状层（OPL）中包含三个独立耦合的HC网络，鉴定为H1和H2体细胞树突，和H1AT。在每个锥蒂，H1和H2树突状尖端与靠近视锥突触带的GluA4亚基的共定位表明，从视锥细胞到H1和H2水平细胞的谷氨酸信号是由α-氨基-3-羟基-5-甲基-4-异恶唑丙酸（AMPA）受体介导的。
