Synaptic clustering of GABAC receptor ρ-subunits in the rat retina
Synaptic clustering of GABAC receptor ρ-subunits in the rat retina
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DOI：
10.1046/j.1460-9568.1998.00005.x
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发表时间：
1998-01-01
影响因子：
3.4
通讯作者：
Wässle, H
中科院分区：
文献类型：
--
作者：
Koulen, P;Brandstätter, JH;Wässle, H
将识别GABA（C）受体的ρ亚基的多克隆抗体应用于大鼠视网膜切片。在内网状层（IPL）中发现了强的点状免疫反应性，电子显微镜显示其代表GABA（C）受体在突触部位的聚集。在出生后的发展弥漫rho免疫反应，第一次观察到在出生后第3天。双极细胞在P7出现明显标记，P10出现点状标记和突触标记。为了显示rho免疫反应性斑点与双极细胞的轴突一致，用抗突触融合蛋白3的抗血清和rho抗血清对视网膜切片进行双重免疫染色。实验结果表明，rho免疫反应点优先位于视杆和视锥双极细胞的轴突终末。为了确定GABA（C）受体rho亚基是否与GABA（A）受体亚基共组装，用亚基特异性抗血清进行双标记实验，用所用的所有抗血清观察到点，推定的突触簇，然而，表达GABA（C）受体的点与含有GABA（A）受体的点不一致。这表明在视网膜中没有GABA（A）和GABA（C）受体亚基共组装的突触GABA受体。还进行了类似的双标记实验，以确定GABA（C）受体和甘氨酸受体是否共定位。它们聚集在不同的突触上。这表明突触GABA（C）受体由rho亚基组成，不与GABA（A）或甘氨酸受体亚基共组装。
Polyclonal antibodies which recognize the rho-subunits of the GABA(C) receptor were applied to sections of the rat retina. Strong punctate immunoreactivity was found in the inner plexiform layer (IPL), which was shown by electron microscopy to represent a clustering of the GABA(C) receptors at synaptic sites. During postnatal development diffuse rho-immunoreactivity was first observed at postnatal day P3. Distinct labelling of bipolar cells appeared at P7 and punctate, synaptic labelling was observed at P10. In order to show that the rho-immunoreactive puncta coincide with the axons of bipolar cells, double immunostainings of retinal sections with an antiserum against syntaxin 3 and with the rho-antiserum were performed. The experiments showed that rho-immunoreactive puncta are preferentially located on the axon terminals of rod and cone bipolar cells. In order to determine whether GABA(C) receptor rho-subunits coassemble with GABA(A) receptor subunits, double-labelling experiments were performed with subunit specific antisera, Punctate, putative synaptic clustering was observed with all antisera applied, however, GABA(C) receptor expressing puncta did not coincide with GABA(A) receptor containing puncta. This suggests that there are no synaptic GABA receptors in the retina in which GABA(A) and GABA(C) receptor subunits are coassembled. Similar double-labelling experiments were also performed to find out whether GABA(C) receptors and glycine receptors are colocalized. They were clustered at different synapses. This suggests that synaptic GABA(C) receptors consist of rho-subunits and are not coassembled with GABA(A)- or glycine-receptor subunits.