Candal Eva, Ferreiro-Galve Susana, Anadón Ramón, Rodríguez-Moldes Isabel
Department of Cell Biology and Ecology, Faculty of Biology, University of Santiago de Compostela, E-15782 Santiago de Compostela, Spain.
Brain Res. 2008 Feb 15;1194:21-7. doi: 10.1016/j.brainres.2007.11.065. Epub 2007 Dec 8.
Gamma-aminobutyric acid (GABA) has been implicated in cell proliferation and differentiation during development. In the present study, immunohistochemical techniques were used to investigate the development of the GABAergic system in the retina of the trout and its relation to markers of differentiation [calretinin (CR), and tyrosine hydroxylase (TH)]. The expression of Pax6, an eye-patterning protein involved in the proliferation and emergence of specific retinal cell types, was also studied. Retinal layering was observed to begin centrally in prehatching embryos, as the first GABAergic cells appeared in the ganglion cell layer (GCL) and inner part of the inner nuclear layer (INL). At hatching, GABAergic cells were also observed in the horizontal cell layer (HCL). In alevins, GABAergic cells and processes spread laterally following retinal growth although they did not invade neuroblastic retinal regions. CR- and Pax6-immunoreactive (ir) cells were first seen in the GCL and the inner part of the INL, whereas sparse TH-ir cells appeared in the INL. In juveniles, GABAergic cells were observed in the GCL, inner part of the INL and HCL, whereas CR-ir cells spread to the outer part of the INL and HCL. A subset of CR-ir in the GCL and of Pax6-ir cells in the GCL and INL showed colocalization with GABAergic markers. This study provides further comparative knowledge about the development of GABAergic system of the retina in teleosts and shows differences and similarities with that reported in fast-developing species such as zebrafish, in which retinal expression of GABA was transient in some populations.
γ-氨基丁酸（GABA）在发育过程中的细胞增殖和分化中发挥作用。在本研究中，采用免疫组织化学技术研究了虹鳟视网膜中GABA能系统的发育及其与分化标志物[钙视网膜蛋白（CR）和酪氨酸羟化酶（TH）]的关系。还研究了参与特定视网膜细胞类型增殖和出现的眼模式蛋白Pax6的表达。观察到视网膜分层在孵化前胚胎的中央开始，此时第一批GABA能细胞出现在神经节细胞层（GCL）和内核层（INL）的内部。孵化时，在水平细胞层（HCL）也观察到GABA能细胞。在仔鱼中，GABA能细胞和突起随着视网膜生长向侧面扩散，尽管它们没有侵入视网膜神经母细胞区域。CR和Pax6免疫反应性（ir）细胞首先出现在GCL和INL的内部，而稀疏的TH-ir细胞出现在INL中。在幼鱼中，在GCL、INL内部和HCL中观察到GABA能细胞，而CR-ir细胞扩散到INL和HCL的外部。GCL中的一部分CR-ir细胞以及GCL和INL中的Pax6-ir细胞与GABA能标志物共定位。本研究提供了关于硬骨鱼视网膜GABA能系统发育的进一步比较知识，并显示了与快速发育物种（如斑马鱼）报道的差异和相似之处，在斑马鱼中，某些群体中GABA的视网膜表达是短暂的。
