Dopaminergic and GABAergic amacrine cells are direct targets of melatonin:: Immunocytochemical study of mt1 melatonin receptor in guinea pig retina
Dopaminergic and GABAergic amacrine cells are direct targets of melatonin:: Immunocytochemical study of mt1 melatonin receptor in guinea pig retina
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DOI：
10.1017/s0952523800171068
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发表时间：
2000-01-01
影响因子：
1.9
通讯作者：
Brown, GM
中科院分区：
文献类型：
--
作者：
Fujieda, H;Scher, J;Brown, GM
采用肽特异性抗mt(1)受体抗体免疫细胞化学方法研究了褪黑激素受体mt(1)在豚鼠视网膜中的分布。豚鼠视网膜的Western blots显示单条条带对抗mt(1)抗体产生约37千道尔顿（kD）的免疫反应。mt(1)受体在神经节细胞的细胞体中检测到最强烈的免疫反应性。它们的树突和轴突也被免疫标记。无突细胞亚群、内丛状层和外丛状层也表现出中度至弱的免疫标记。mt(1)阳性的无突细胞位于内核层的玻璃体边界或移位在神经节细胞层。使用mt(1)受体抗体和酪氨酸羟化酶的双重免疫标记显示，大多数多巴胺能无毛细胞表现出mt(1)免疫反应性。ICA型多巴胺能细胞mt(1)阳性，2CA型细胞mt(1)免疫反应较少。通过对mt(1)受体和GABA的双重免疫标记，超过50%的mt(1)-免疫反应性无毛细胞被证明是GABA能神经元。大约三分之一的gaba能无分泌细胞被免疫标记为mrl受体。本研究结果证实了mt(1)受体在豚鼠视网膜不同类型神经元细胞中的表达，并为褪黑素通过mt(1)受体对多巴胺能和gaba能无突细胞的直接作用提供了第一个证据。
Distribution of the mt(1) melatonin receptor in the guinea pig retina was immunocytochemically investigated using peptide-specific anfi-mt(1) receptor antibody. Western blots of the guinea pig retina showed a single band at approximately 37 kilodalton (kD) immunoreactive to the anti-mt(1) antibody. The most intense immunoreactivity for the mt(1) receptor was detected in the cell bodies of ganglion cells. Their dendrites and axons were also immunolabeled. Subpopulations of amacrine cells, the inner plexiform layer, and the outer plexiform layer also exhibited moderate to weak immunolabeling. The mt(1)-positive amacrine cells were located either at the vitreal border of the inner nuclear layer or displaced in the ganglion cell layer. Double immunolabeling using antibodies to the mt(1) receptor and tyrosine hydroxylase revealed that the majority of dopaminergic amacrine cells showed mt(1) immunoreactivity. Almost all the ICA type dopaminergic cells were mt(1) positive while the 2CA type cells less frequently exhibited mt(1) immunoreaction. By double immunolabeling for the mt(1) receptor and GABA, more than 50% of the mt(1)-immunoreactive amacrine cells were shown to be GABAergic neurons. Approximately one-third of the GABAergic amacrine cells were immunolabeled for the mrl receptor. The present results demonstrate expression of the mt(1) receptor in diverse neuronal cell types in the guinea pig retina and provide the first evidence for the direct effect of melatonin on dopaminergic and GABAergic amacrine cells via the mt(1) receptor.