Nakadate K
Department of Basic Biology, Educational and Research Center for Pharmacy, Meiji Pharmaceutical University, 2-522-1 Noshio, Kiyose, Tokyo 204-8588, Japan.
Neuroscience. 2015 Apr 30;292:101-11. doi: 10.1016/j.neuroscience.2015.02.035. Epub 2015 Feb 27.
Ocular dominance plasticity is activity dependent, changes in response to eye competition, and is transitory during developmental stages. Lipid rafts have modulatory functions in cellular, physiological, and behavioral processes. Although many of these modulatory roles are mediated by flotillin-1, a lipid raft-associated protein, the ontogenetic changes in the cellular and subcellular distribution patterns of flotillin-1 are unclear. I investigated the developmental pattern of the distribution of flotillin-1 in the rat visual cortex with immunohistochemistry at both light and electron microscopic levels. An affinity-purified anti-flotillin-1 antibody reacted with a single band of about 40-50 kDa in total proteins prepared from the rat visual cortex. Flotillin-1 levels transiently increased on postnatal days 21-35. Flotillin-1 immunoreactivity at 3 weeks of age was broadly distributed though all visual cortical layers, but it exhibited a relatively higher density in layers II/III and V/VI. Flotillin-1 immunoreactivity at 3 months of age was significantly decreased compared with that at 3 weeks of age. Strong flotillin-1 immunoreactivity was observed in both neuronal perikarya and processes at 3 weeks of age. Double-labeling experiments with anti-microtubule-associated protein 2, anti-neurofilament, anti-synaptophysin, anti-vesicular glutamate transporter 1, anti-vesicular glutamate transporter 2, anti-glial fibrillary acidic protein, and flotillin-1 mainly labeled the somata of excitatory neurons and corticocortical synapses. Some flotillin-1 was distributed in excitatory neuron axons, thalamocortical synapses, astrocytes, oligodendrocytes, and microglial cells. Immunoelectron microscopy revealed numerous regions of flotillin-1 immunoreactivity near the rough endoplasmic reticulum in neurons and presynaptic regions at 3 weeks of age. These findings illustrate early developmental changes in the cellular and subcellular localization of flotillin-1 protein in the rat visual cortex. Moreover, the ultrastructural distribution of flotillin-1 immunoreactivity suggested that flotillin-1 was transported mainly into presynaptic terminals where it exerts effects at the presynaptic sites of excitatory and inhibitory neurons.
眼优势可塑性依赖于活动，随眼竞争而变化，且在发育阶段是短暂的。脂筏在细胞、生理和行为过程中具有调节功能。尽管这些调节作用许多是由脂筏相关蛋白弗洛蒂林-1介导的，但弗洛蒂林-1在细胞和亚细胞分布模式中的个体发生变化尚不清楚。我用免疫组织化学方法在光镜和电镜水平研究了弗洛蒂林-1在大鼠视皮层中的发育分布模式。一种亲和纯化的抗弗洛蒂林-1抗体与从大鼠视皮层制备的总蛋白中一条约40-50 kDa的单带发生反应。弗洛蒂林-1水平在出生后第21-35天短暂升高。3周龄时，弗洛蒂林-1免疫反应性广泛分布于所有视皮层层，但在II/III层和V/VI层表现出相对较高的密度。3月龄时，弗洛蒂林-1免疫反应性与3周龄时相比显著降低。在3周龄时，在神经元胞体和突起中均观察到强弗洛蒂林-1免疫反应性。用抗微管相关蛋白2、抗神经丝、抗突触素、抗囊泡谷氨酸转运体1、抗囊泡谷氨酸转运体2、抗胶质纤维酸性蛋白和弗洛蒂林-1进行的双标实验主要标记了兴奋性神经元的胞体和皮质皮质突触。一些弗洛蒂林-1分布在兴奋性神经元轴突、丘脑皮质突触、星形胶质细胞、少突胶质细胞和小胶质细胞中。免疫电子显微镜显示，3周龄时，在神经元的粗面内质网附近和突触前区域有大量弗洛蒂林-1免疫反应性区域。这些发现说明了大鼠视皮层中弗洛蒂林-1蛋白在细胞和亚细胞定位上的早期发育变化。此外，弗洛蒂林-1免疫反应性的超微结构分布表明，弗洛蒂林-1主要被转运到突触前终末，在兴奋性和抑制性神经元的突触前位点发挥作用。
