Whole-cell electrophysiology of gonadotropin-releasing hormone neurons that express green fluorescent protein in the terminal nerve of transgenic medaka (Oryzias latipes)
Whole-cell electrophysiology of gonadotropin-releasing hormone neurons that express green fluorescent protein in the terminal nerve of transgenic medaka (Oryzias latipes)
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DOI：
10.1095/biolreprod.105.042721
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发表时间：
2005-12-01
影响因子：
3.6
通讯作者：
Okubo, K
中科院分区：
文献类型：
--
作者：
Wayne, NL;Kuwahara, K;Okubo, K
促性腺激素释放激素 (GnRH) 控制脊椎动物的繁殖。大多数研究都集中在下丘脑中最终控制性腺功能的 GnRH 神经元群体。然而，迄今为止研究的所有脊椎动物都有两到三个解剖学上不同的 GnRH 神经元群体，它们表达不同形式的这种激素。本研究的目的是开发一种新模型来研究与嗅球相关的终末神经（TN）中的 GnRH 神经元群体，然后表征它们的动作电位放电模式，为了解这些神经元在调节生殖中的作用提供基础。产生了转基因青鳉 (Oryzias latipes) 的稳定品系，其中包含与绿色荧光蛋白 (GFP) 连接的鲑鱼 GnRH (Gnrh3) 启动子的 DNA 构建体在 TN-GnRH3 神经元中表达。这群 GnRH 神经元位于大脑腹侧表面或附近，使其成为电生理分析的理想位置。在电流钳模式下对来自成年男性完整大脑的这些神经元进行了全细胞和松散记录，其中传入和传出神经连接保持完整。我们记录的所有 TN-GnRH3GFP 神经元均显示出自发动作电位放电的跳动模式。动作电位被河豚毒素阻断，表明它们是由电压敏感的 Na+ 电流产生的；然而，阈下膜电位的振荡仍然存在。目前的结果表明，这种转基因鱼将为研究下丘脑外 GnRH 神经元群体的细胞生理学提供一个极好的模型。
Conadotropin-releasing hormone (GnRH) controls reproduction in vertebrates. Most studies have focused on the population of GnRH neurons in the hypothalamus that ultimately controls gonadal function. However, all vertebrates studied to date have two to three anatomically distinct populations of GnRH neurons that express different forms of this hormone. The purpose of the present study was to develop a new model for studying the population of GnRH neurons in the terminal nerve (TN) associated with the olfactory bulb and then to characterize their pattern of action potential firing to provide a foundation for understanding the role of these neurons in regulating reproduction. A stable line of transgenic medaka (Oryzias latipes) was generated in which a DNA construct containing the salmon GnRH (Gnrh3) promoter linked to green fluorescent protein (GFP) was expressed in TN-GnRH3 neurons. This population of GnRH neurons is located at or near the ventral surface of the brain, making them ideally situated for electro-physiological analysis. Whole-cell and loose-patch recordings in current-clamp mode were performed on these neurons from excised, intact brains of adult males in which afferent and efferent neural connections remained intact. All TN-GnRH3GFP neurons that we recorded showed a beating pattern of spontaneous action potential firing. Action potentials were blocked by tetrodotoxin, indicating they are generated by a voltage-sensitive Na+ current; however, an oscillation in subthreshold membrane potential persisted. The present results indicate that this transgenic fish will provide an excellent model for studying the cell physiology of an extrahypothalamic population of GnRH neurons.