Nitrergic dendrites in the superficial layers of the rat superior colliculus: Retinal afferents and alternatively spliced isoforms in normal and deafferented animals
Nitrergic dendrites in the superficial layers of the rat superior colliculus: Retinal afferents and alternatively spliced isoforms in normal and deafferented animals
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DOI：
10.1002/jnr.10494
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发表时间：
2003-02-01
影响因子：
4.2
通讯作者：
Mendez-Otero, R
中科院分区：
文献类型：
--
作者：
Batista, CMC;Carneiro, K;Mendez-Otero, R
大鼠上丘（sSC）的浅层接受来自视网膜的神经支配，包括氮能神经元。我们之前的研究表明，在sSC中，除氮能神经元最近端树突外，眼去核显著降低了所有神经元的NADPH脱氢酶染色。我们使用免疫细胞化学方法在光镜和电子显微镜下检测神经元一氧化氮合酶（nNOS），并在不同存活时间的双侧眼去核，以确定视网膜输入的直接和间接损失对表观一氧化氮合酶数量和亚细胞分布的调节变化。此外，我们还使用SDS-PAGE和免疫印迹技术来检测正常和缺血动物的选择性剪接同种异构体。我们的研究结果表明，明确识别的视网膜终端接触氮能神经元。在正常树突中，nNOS免疫反应性几乎完全分布在树突的细胞质内和突触连接处的突触后膜上，并与内质网、核糖体和线粒体外膜相关。相比之下，nNOS标记在无视网膜投射的sSC中显著减少，并且只能观察到与线粒体膜和突触后密度相关。sSC可溶性部分的免疫印迹显示，与正常丘中的a对应物相比，P异构体的比例惊人地高，这表明去核后异构体的比例增加，或至少保持相同的比例。我们认为，在去核动物中观察到的sSC细胞超微结构的改变可能是由于sSC细胞对视网膜传入事件的移除做出了塑性反应。(C) 2002 Wiley-Liss, Inc。
The superficial layers of the rat superior colliculus (sSC) receive innervation from the retina and include nitrergic neurons. We have shown previously that in sSC, eye enucleation reduces NADPH diaphorase staining considerably in all but the most proximal dendrites of nitrergic neurons. We have used immunocytochemistry for neuronal nitric oxide synthase (nNOS) at light and electron microscopic levels and bilateral eye enucleation with varied survival times to determine the regulatory changes imposed by the direct and indirect loss of retinal input on apparent nNOS amount and subcellular distribution. In addition, we have used SDS-PAGE and immunoblotting to test alternatively spliced isoforms in normal and deafferented animals. Our results show that unambiguously identified retinal terminals contact nitrergic neurons. In normal dendrites, nNOS immunoreactivity was distributed almost completely within the cytoplasm of the dendrite and along the postsynaptic membrane at synaptic junctions, in association with endoplasmic reticulum, ribosomes and external mitochondrial membranes. In contrast, nNOS labeling was greatly reduced in sSC deprived of retinal projections, and could only be observed in association with mitochondrial membranes and postsynaptic densities. Immunoblots of the soluble fraction from sSC revealed a surprisingly high proportion of the P isoform with respect to the a counterpart in normal colliculi, suggesting an increase in isoform proportion after enucleation, or at least maintenance of the same proportion. It is suggested that ultrastructural alterations observed in sSC cells of enucleated animals may be consequent to plastic reactions of the sSC cells in response to the removal of retinal afferents. (C) 2002 Wiley-Liss, Inc.