Sexual dimorphism in extent of axonal sprouting in rat hippocampus.
Sexual dimorphism in extent of axonal sprouting in rat hippocampus.
复制标题
大鼠海马轴突萌芽程度的性别二态性。
作者：
R. Loy;T. Milner
交感神经轴突，通常支配脑外血管，发芽到海马结构的内侧隔核或海马伞病变后，在成年雌性大鼠去神经支配的地区。成年男性的类似病变也会引起交感神经向内生长;然而，异常轴突的数量大大减少，它们的分布也发生了改变。在成年男性的交感神经轴突不发出侧支层的区域CA 3或分子层或深门区的齿状回，因为他们在成年女性。在青少年的病变导致更有力的发芽比他们的成年同行。在年轻的男性中，异常轴突更广泛地分布在齿状分子层中;在年轻的女性中，轴突只是在与成年人相同的区域内发出更多的侧枝。这种对中枢神经系统损伤的性二态反应表明，发芽受到成熟海马系统的激素环境的影响，或者该脑区（如下丘脑）可能由于发育期间暴露于性类固醇而表达永久的形态或生理差异。
Sympathetic axons, normally innervating the extracerebral vasculature, sprout into denervated regions of the hippocampal formation after lesions of the medial septal nucleus or fimbria in adult female rats. Similar lesions in adult males also elicit the sympathetic ingrowth; however, the number of anomalous axons is greatly reduced and their distribution is altered. In adult males the sympathetic axons do not send out collaterals within the stratum oriens of region CA3 or the molecular layer or deep hilar regions of the area dentata, as they do in adult females. Lesions in juveniles of both sexes result in more vigorous sprouting than in their adult counterparts. In the young males the anomalous axons are distributed more extensively into the dentate molecular layer; in the young females the axons merely send out more collaterals within the same regions as in the adults. This sexually dimorphic response to central nervous system damage suggests either that the sprouting is affected by the hormonal environment of the mature hippocampal system or that this brain region, like the hypothalamus, may express permanent morphological or physiological differences as a result of exposure to sex steroids during development.