Postnatal remodeling of dendritic structure and spine density in gonadotropin-releasing hormone neurons
Postnatal remodeling of dendritic structure and spine density in gonadotropin-releasing hormone neurons
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DOI：
10.1210/en.2006-0296
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发表时间：
2006-08-01
期刊：
影响因子：
4.8
通讯作者：
Herbison, Allan E.
中科院分区：
文献类型：
--
作者：
Cottrell, Elizabeth C.;Campbell, Rebecca E.;Herbison, Allan E.
GnRH神经元代表控制性腺功能的神经元网络的输出细胞。它们的激活启动青春期的开始，但其潜在的机制仍不清楚。使用GnRH-绿色荧光蛋白小鼠模型，我们已经能够在急性脑切片制备中用生物胞素填充单个GnRH神经元，以检查其在青春期的形态学特征。青春期前雄性小鼠[出生后第10-15天（PND 10 -15）]的GnRH神经元的树突棘和体棘数量是成年雄性小鼠的一半（> PND 60; P < 0.05），但令人惊讶的是，树突树更复杂，分支点是成年雄性小鼠的5倍（P < 0.05）。在GnRH-绿色荧光蛋白小鼠的灌注固定组织中，体内检查体细胞和近端树突棘数量的实验显示，与PND 10雄性小鼠相比，成年GnRH神经元上的棘数量约为2倍（P < 0.01）。与反映兴奋性输入变化的棘密度变化相反，共聚焦免疫荧光研究显示，青春期前和成年雄性小鼠GnRH索马或近端树突附近的囊泡γ-氨基丁酸转运蛋白免疫反应元件数量无差异。在体内（PND 3，-10，和-35和成人）树突状树结构的评价实验表明，GnRH神经元位于吻侧视前区，但不是内侧隔，表现出更复杂的分支模式在PND 10，但这是成人一样的PND 35。这些研究证实了GnRH神经元中意外的树突树重塑，并提供了在整个青春期对GnRH神经元的直接兴奋性输入增加的证据。
The GnRH neurons represent the output cells of the neuronal network controlling gonadal function. Their activation initiates the onset of puberty, but the underlying mechanisms remain unclear. Using a GnRH-green fluorescent protein mouse model, we have been able to fill individual GnRH neurons with biocytin in the acute brain slice preparation to examine their morphological characteristics across puberty. GnRH neurons in prepubertal male mice [postnatal d 10-15 (PND10-15)] exhibited half as many dendritic and somal spines as adult male mice (> PND60; P < 0.05) but, surprisingly, a much more complex dendritic tree with 5-fold greater branch points (P < 0.05). Experiments examining somal and proximal dendritic spine numbers in vivo, in perfusion-fixed tissue from GnRH-green fluorescent protein mice, revealed the same pattern of approximately twice as many spines on adult GnRH neurons compared with PND10 male mice (P < 0.01). In contrast to the spine density alterations, reflecting changing excitatory input, confocal immunofluorescence studies revealed no differences in the numbers of vesicular gamma-aminobutyric acid transporter-immunoreactive elements adjacent to GnRH soma or proximal dendrites in prepubertal and adult male mice. Experiments evaluating dendritic tree structure in vivo (PND3, -10, and -35 and adult) revealed that GnRH neurons located in the rostral preoptic area, but not the medial septum, exhibited a more complex branching pattern at PND10, but that this was adult-like by PND35. These studies demonstrate unexpected dendritic tree remodeling in the GnRH neurons and provide evidence for an increase in direct excitatory inputs to GnRH neurons across the time of puberty.