Identification of amacrine neurons with a glycinergic and GABAergic phenotype in the mouse retina.
Identification of amacrine neurons with a glycinergic and GABAergic phenotype in the mouse retina.
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DOI：
10.18103/mra.v10i1.2624
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发表时间：
2022-01
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影响因子：
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通讯作者：
J. Pérez-León;Annie Espinal-Centeno;Zelene Mendoza-Gonzalez;Alejandra Camacho;A. Lopez;Rosa Perez;M. Miranda
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作者：
J. Pérez-León;Annie Espinal-Centeno;Zelene Mendoza-Gonzalez;Alejandra Camacho;A. Lopez;Rosa Perez;M. Miranda
哺乳动物视网膜中的无长突神经元包括多种不同的细胞类型，它们具有不同的特性和功能，用于整合和调制提供给输出神经元的信号。大多数细胞使用甘氨酸或GABA作为抑制性神经递质，并分别表达甘氨酸转运蛋白1(GlyT1)或谷氨酸脱羧酶(GAD67)和GABA转运蛋白(GAT1和GAT3)，分别作为甘氨酸能和GABA能标记。我们报道了一个新的无长突神经元亚群，在野生型C57BL/6J小鼠和两个转基因系的视网膜中同时表达GABA能和甘氨酸能标记。在甘氨酸转运蛋白2控制下表达EGFP的转基因品系的视网膜切片中，EGFP仅在抑制性无长突神经元的胞体和树突中表达，经鉴定它们对Synaxin 1A具有免疫反应性。所有甘氨酸能神经元和大部分GABA能无长突神经元都含有EGFP，其中8-10%的GlyT1阳性神经元还被GAD67、GAT1或GAT3标记。这些发现在GAD67启动子和两种不同的抗GlyT1抗体下表达EGFP的野生型和小鼠的视网膜中得到证实，表明存在一个具有双重表型的亚群。此外，在两种小鼠体内网状层的几个区域内，EGFP阳性树突与GlyR亚单位和支架蛋白Geporrin并列分布，证明了这些神经元的甘氨酸能特征。这种双重表型也存在于原代培养的视网膜中，分离的神经元GlyT1和GAD67或GAT1/3呈阳性。总之，这些数据为甘氨酸能/GABA能无长突神经元亚群的双重抑制提供了有力的证据。两种神经递质的共同释放可能有助于加强突触过度兴奋状态下对神经节细胞的抑制作用。
The amacrine neurons in the mammalian retina comprise a large variety of cell types with distinct properties and functions that serve to integrate and modulate signals presented to output neurons. The majority of them use either glycine or GABA as inhibitory neurotransmitters and express the glycine transporter 1 (GlyT1) or glutamic acid decarboxylase (GAD67) and GABA transporters (GAT1 and GAT3), as a glycinergic or GABAergic marker respectively. We report here a novel subpopulation of amacrine neurons expressing both, GABAergic and glycinergic markers, in retinas from wild-type C57BL/6J mice and two transgenic lines. In retinal sections from the transgenic line expressing eGFP under the control of the glycine transporter 2, eGFP expression was exclusively found in cell bodies and dendrites of inhibitory amacrine neurons, identified for their immunoreactivity to syntaxin 1A. All of the glycinergic and a large portion of the GABAergic amacrine neurons contained eGFP; of these, 8-10% of GlyT1 positive neurons were also labeled either with GAD67, GAT1 or GAT3. These findings were confirmed in retinas from a wild-type and a mouse line expressing eGFP under the GAD67 promoter and two different anti-GlyT1 antibodies, showing the presence of a subpopulation with a dual phenotype. Moreover, eGFP-positive dendrites on both mouse lines were found juxtaposed to GlyR subunits and the scaffold protein gephyrin in several areas of the inner plexiform layer, demonstrating the glycinergic character of these neurons. This dual phenotype was also demonstrated in primary retina cultures, in which isolated neurons were positive for GlyT1 and GAD67 or GAT1/3. Altogether, these data provide compelling evidence of a subpopulation of dual inhibitory, glycinergic/GABAergic amacrine neurons. The co-release of both neurotransmitters may serve to strengthen the inhibition on ganglion cells under synaptic hyperexcitability.