Flanagan-Cato L M, Calizo L H, Daniels D
Department of Psychology and Institute for Neurological Sciences, University of Pennsylvania, 3815 Walnut Street, Philadelphia, Pennsylvania 19104-6196, USA.
Horm Behav. 2001 Sep;40(2):178-82. doi: 10.1006/hbeh.2001.1679.
Estrogen acts in the hypothalamic ventromedial nucleus (VMH) of female rats to promote sexual behavior, as typified by the lordosis response. Morphological changes in the VMH, such as increased synaptic profiles and increased dendritic spines, suggest that estrogen may modulate behavior by altering VMH synaptic organization. To understand the significance of these changes, this laboratory has been investigating the functional classes of lordosis-relevant neurons and their local connectivity. A neurotropic virus, pseudorabies virus (PRV), was used to transneuronally label the CNS network that controls the lordosis-producing muscles. When PRV was placed in the lumbar epaxial muscles, it was sequentially detected in the lumbar ventral horn, the medullary reticular formation, the periaqueductal gray, and finally the VMH. Subsequent analysis showed that the population of VMH neurons that were initially infected with PRV largely resided beyond the cluster of estrogen receptor-containing neurons. In a separate study, VMH neurons were visualized with Lucifer yellow, and their morphology was analyzed using confocal microscopy. Such analysis confirmed that estrogen treatment increased dendritic spines in the VMH. The particular VMH neurons in this study did not express nuclear estrogen receptor, which suggests that estrogen can increase spine density indirectly. These results represent initial steps toward unraveling the local circuit that mediates estrogenic action on a specific reproductive behavior.
雌激素作用于雌性大鼠的下丘脑腹内侧核（VMH），以促进性行为，如以脊柱前凸反应为典型表现。VMH的形态学变化，如突触轮廓增加和树突棘增多，表明雌激素可能通过改变VMH的突触组织来调节行为。为了理解这些变化的意义，本实验室一直在研究与脊柱前凸相关的神经元的功能类别及其局部连接。一种嗜神经性病毒，伪狂犬病病毒（PRV），被用于跨神经元标记控制产生脊柱前凸的肌肉的中枢神经系统网络。当将PRV置于腰部轴上肌时，它依次在腰髓腹角、延髓网状结构、导水管周围灰质中被检测到，最终在VMH中被检测到。随后的分析表明，最初感染PRV的VMH神经元群体主要位于含雌激素受体的神经元簇之外。在另一项研究中，用荧光黄对VMH神经元进行可视化，并使用共聚焦显微镜分析其形态。这样的分析证实了雌激素处理增加了VMH中的树突棘。本研究中特定的VMH神经元不表达核雌激素受体，这表明雌激素可以间接增加棘密度。这些结果代表了朝着阐明介导雌激素对特定生殖行为作用的局部回路迈出的初步步骤。
