A novel type of interplexiform amacrine cell in the mouse retina
A novel type of interplexiform amacrine cell in the mouse retina
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DOI：
10.1111/j.1460-9568.2009.06808.x
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发表时间：
2009-07-01
影响因子：
3.4
通讯作者：
Weiler, Reto
中科院分区：
文献类型：
--
作者：
Dedek, Karin;Breuninger, Tobias;Weiler, Reto
哺乳动物的视网膜由种类繁多的无毛细胞组成，这些细胞具有不同的特性和功能。本文描述了小鼠视网膜中一种新的丛状无突细胞类型。利用转基因小鼠突变体，在几种视网膜细胞类别中表达增强绿色荧光蛋白（EGFP）基因，而不是connexin45的编码DNA，其中单个无痘细胞群体的标记最为显著。EGFP和不同标记蛋白的染色表明，这些无突细胞是网状的：它们在网状内层的S4/5层分层，并向网状外层发送突起。这些细胞命名为IPA-S4/5细胞。它们属于中场无毛细胞群，通过连接蛋白45与其他无毛细胞同源或异源偶联。免疫染色显示IPA-S4/5细胞具有GABA能并表达GAT-1， GAT-1是一种质膜结合的GABA转运体，可能参与非囊性GABA释放。为了表征IPA-S4/5细胞的光响应，我们在视网膜切片上进行膜片钳记录。与它们在内丛状层的ON膜下分层一致，细胞在光刺激下去极化，在光刺激下瞬态超极化。细胞对绿光（578 nm）和蓝光（400 nm）的响应表明，它们从接触M-锥和s -锥的锥双极细胞接收输入，可能减少了s -锥输入。描述了一种新型的丛状ON无分泌细胞，它是强偶联的，使用GABA而不是多巴胺作为其神经递质。
Mammalian retinas comprise an enormous variety of amacrine cells with distinct properties and functions. The present paper describes a new interplexiform amacrine cell type in the mouse retina. A transgenic mouse mutant was used that expressed the gene for the enhanced green fluorescent protein (EGFP) instead of the coding DNA of connexin45 in several retinal cell classes, among which a single amacrine cell population was most prominently labelled. Staining for EGFP and different marker proteins showed that these amacrine cells are interplexiform: they stratify in stratum S4/5 of the inner plexiform layer and send processes to the outer plexiform layer. These cells were termed IPA-S4/5 cells. They belong to the group of medium-field amacrine cells and are coupled homologously and heterologously to other amacrine cells by connexin45. Immunostaining revealed that IPA-S4/5 cells are GABAergic and express GAT-1, a plasma-membrane-bound GABA transporter possibly involved in non-vesicular GABA release. To characterize the light responses of IPA-S4/5 cells, patch-clamp recordings in retinal slices were made. Consistent with their stratification in the ON sublamina of the inner plexiform layer, cells depolarized in response to light ON stimuli and transiently hyperpolarized in response to light OFF. Responses of cells to green (578 nm) and blue (400 nm) light suggest that they receive input from cone bipolar cells contacting both M- and S-cones, possibly with reduced S-cone input. A new type of interplexiform ON amacrine cell is described, which is strongly coupled and uses GABA but not dopamine as its neurotransmitter.