Tyler C J, Fite K V, Devries G J
Neuroscience and Behavior Program, University of Massachusetts, Amherst 01003-7710, USA.
J Comp Neurol. 1995 Mar 13;353(3):439-50. doi: 10.1002/cne.903530311.
Immunohistochemistry was used to survey the distribution of glutamic acid decarboxylase (GAD), the synthesizing enzyme for gamma-aminobutyric acid (GABA), throughout the visual system of the frog Rana pipiens. GAD-like immunoreactivity (GAD-LI) was assessed in the retina, in primary retinorecipient targets, and in thalamic nuclear groups postsynaptic to primary retinal terminal zones. Within the retina, the inner plexiform layer displayed intense GAD-LI, but immunoreactivity was absent in the ganglion cell layer (GCL). Putative amacrine, bipolar, and horizontal cell somata were also labeled. Centrally, GAD-LI was observed in all primary visual nuclei. Dense, GAD-like immunoreactive punctate structures (puncta), presumably terminals, were observed in the pretectal nucleus lentiformis mesencephali, posterior thalamic neuropil, and uncinate neuropil. GAD-like immunoreactive puncta were noted in several laminae of the optic tectum, with the highest concentrations located within the 9th and 8th laminae. Moderate numbers of GAD-like immunoreactive puncta were found in the mesencephalic nucleus of the basal optic root, and two thalamic neuropils--corpus geniculatum and neuropil of Bellonci. The ventrolateral area, posterocentral nucleus, and posterolateral nucleus all contained sparse amounts of GAD-LI. These observations suggest that GABA plays an important physiological role in all central visual areas of Rana pipiens.
免疫组织化学被用于研究γ-氨基丁酸（GABA）合成酶谷氨酸脱羧酶（GAD）在牛蛙视觉系统中的分布情况。在视网膜、视网膜一级投射靶点以及视网膜一级终末区域突触后的丘脑核团中评估了GAD样免疫反应性（GAD-LI）。在视网膜内，内网状层显示出强烈的GAD-LI，但神经节细胞层（GCL）中没有免疫反应性。假定的无长突细胞、双极细胞和水平细胞的胞体也被标记。在中枢，在所有一级视觉核团中都观察到了GAD-LI。在中脑豆状核前核、丘脑后神经毡和钩状神经毡中观察到密集的、GAD样免疫反应性点状结构（小点），推测为终末。在视顶盖的几个层中发现了GAD样免疫反应性小点，最高浓度位于第9层和第8层。在基底视根的中脑核以及两个丘脑神经毡——外侧膝状体和贝隆奇神经毡中发现了中等数量的GAD样免疫反应性小点。腹外侧区、后中央核和后外侧核都含有少量的GAD-LI。这些观察结果表明，GABA在牛蛙的所有中枢视觉区域中发挥着重要的生理作用。
