Guirado Ramon, Perez-Rando Marta, Sanchez-Matarredona David, Castillo-Gómez Esther, Liberia Teresa, Rovira-Esteban Laura, Varea Emilio, Crespo Carlos, Blasco-Ibáñez José Miguel, Nacher Juan
Cell Biology Department, Neurobiology Unit and Program in Basic and Applied Neurosciences, Universitat de València, Valencia, Spain Current address: Neuroscience Center, University of Helsinki, Helsinki, Finland.
Cell Biology Department, Neurobiology Unit and Program in Basic and Applied Neurosciences, Universitat de València, Valencia, Spain.
Cereb Cortex. 2014 Nov;24(11):3014-24. doi: 10.1093/cercor/bht156. Epub 2013 Jun 17.
Excitatory neurons undergo dendritic spine remodeling in response to different stimuli. However, there is scarce information about this type of plasticity in interneurons. The polysialylated form of the neural cell adhesion molecule (PSA-NCAM) is a good candidate to mediate this plasticity as it participates in neuronal remodeling and is expressed by some mature cortical interneurons, which have reduced dendritic arborization, spine density, and synaptic input. To study the connectivity of the dendritic spines of interneurons and the influence of PSA-NCAM on their dynamics, we have analyzed these structures in a subpopulation of fluorescent spiny interneurons in the hippocampus of glutamic acid decarboxylase-enhanced green fluorescent protein transgenic mice. Our results show that these spines receive excitatory synapses. The depletion of PSA in vivo using the enzyme Endo-Neuraminidase-N (Endo-N) increases spine density when analyzed 2 days after, but decreases it 7 days after. The dendritic spine turnover was also analyzed in real time using organotypic hippocampal cultures: 24 h after the addition of EndoN, we observed an increase in the apparition rate of spines. These results indicate that dendritic spines are important structures in the control of the synaptic input of hippocampal interneurons and suggest that PSA-NCAM is relevant in the regulation of their morphology and connectivity.
兴奋性神经元会根据不同刺激进行树突棘重塑。然而，关于中间神经元中这种可塑性的信息却很少。神经细胞黏附分子的多唾液酸化形式（PSA-NCAM）是介导这种可塑性的一个很好的候选分子，因为它参与神经元重塑，并且在一些成熟的皮质中间神经元中表达，这些中间神经元的树突分支、棘密度和突触输入都有所减少。为了研究中间神经元树突棘的连接性以及PSA-NCAM对其动态变化的影响，我们在谷氨酸脱羧酶增强型绿色荧光蛋白转基因小鼠海马体中的一群荧光棘状中间神经元中分析了这些结构。我们的结果表明，这些棘接受兴奋性突触。在体内使用内切神经氨酸酶N（Endo-N）消耗PSA后，在2天后分析时棘密度增加，但在7天后降低。我们还使用海马脑片培养实时分析了树突棘的更新情况：添加EndoN后24小时，我们观察到棘的出现率增加。这些结果表明，树突棘是控制海马体中间神经元突触输入的重要结构，并表明PSA-NCAM在调节其形态和连接性方面具有相关性。
