Sexual dimorphism in the organization of the rat hypothalamic infundibular area
Sexual dimorphism in the organization of the rat hypothalamic infundibular area
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DOI：
10.1016/j.neuroscience.2006.05.041
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发表时间：
2006-01-01
期刊：
影响因子：
3.3
通讯作者：
Tramu, G.
中科院分区：
文献类型：
--
作者：
Ciofi, P.;Leroy, D.;Tramu, G.
下丘脑漏斗区位于血脑屏障之外，包括感知循环物质的腹内侧弓状核（vmARC）和神经激素释放到下丘脑垂体脉管系统的正中隆起（ME）。这个集成的功能单元在内分泌控制中至关重要，可调节神经内分泌输出以反馈信息。尽管雄性和雌性的生理机能不同，但这种功能单位在性别之间的组织方式并没有出现差异。利用免疫细胞化学，我们首次在成年大鼠中描述了其轴突接线的显着性别差异，这种差异是由含有神经肽神经激肽 B (NKB) 和强啡肽的内在谷氨酸能神经元造成的。在男性中，NKB 神经元将轴突发送到 vmARC 和 ME 的毛细血管（仅在促性腺激素释放激素 (GnRH) 轴突终止的地方）。电子显微镜显示，NKB 轴突以有孔毛细血管周围的单细胞屏障为目标（除了 GnRH 轴突），表明对区域双向渗透性的控制。在雌性中，NKB 神经元将轴突发送到 vmARC 的神经桩，这表明对其感觉神经元的直接控制。通过手术分离 ARC-ME 复合体和共聚焦显微镜研究 NKB 神经元的其他投射，它们不是性别二态性的，并且针对控制生殖和代谢的整合中心和神经内分泌中心，表明对内分泌功能有广泛的影响。这些观察表明，促进下丘脑通透性和对反馈信息敏感性的机制是性别上的 二态性，使得漏斗区成为成人脉动激素分泌模式中男性与女性差异的产生的特殊部位。 (c) 2006 年国际广播组织。由爱思唯尔有限公司出版。保留所有权利。
The hypothalamic infundibular area is located outside the blood-brain barrier and includes, the ventromedial arcuate nucleus (vmARC) sensing circulating substances, and the median eminence (ME) where neurohormones are released into the hypothalarno-hypophysial vasculature. This integrated functional unit, pivotal in endocrine control, adjusts neuroendocrine output to feedback information. Despite a differing physiology in males and females, this functional unit has not appeared differently organized between sexes.Using immunocytochemistry, we describe here for the first time in adult rats, a conspicuous sex-difference in its axonal wiring by intrinsic glutarnatergic neurons containing the neuropeptides neurokinin B (NKB) and dynorphin. In the male, NKB neurons send axons to capillary vessels of the vmARC and of the ME (only where gonadotropin-releasing hormone (GnRH) axons terminate). Electron microscopy revealed that NKB axons target the barrier of tanycytes around fenestrated capillary vessels (in addition to GnRH axons), suggesting a control of regional bidirectional permeability. In the female, NKB neurons send axons to the neuropile of the vmARC, suggesting a direct control of its sensor neurons. The other projections of NKB neurons, studied by surgical isolation of the ARC-ME complex and confocal microscopy, are not sexually dimorphic and target both integrative and neuroendocrine centers controlling reproduction and metabolism, suggesting a broad influence over endocrine function.These observations demonstrate that the mechanisms subserving hypothalamic permeability and sensitivity to feedback information are sexually dimorphic, making the infundibular area a privileged site of generation of the male-to-female differences in the adult pattern of pulsatile hormonal secretions. (c) 2006 IBRO. Published by Elsevier Ltd. All rights reserved.