Yip Siew Hoong, Boehm Ulrich, Herbison Allan E, Campbell Rebecca E
Centre for Neuroendocrinology and Department of Physiology, School of Medical Sciences, University of Otago, Dunedin, New Zealand 9054.
Endocrinology. 2015 Jul;156(7):2582-94. doi: 10.1210/en.2015-1131. Epub 2015 Apr 9.
Kisspeptin neurons play an essential role in the regulation of fertility through direct regulation of the GnRH neurons. However, the relative contributions of the two functionally distinct kisspeptin neuron subpopulations to this critical regulation are not fully understood. Here we analyzed the specific projection patterns of kisspeptin neurons originating from either the rostral periventricular nucleus of the third ventricle (RP3V) or the arcuate nucleus (ARN) using a cell-specific, viral-mediated tract-tracing approach. We stereotaxically injected a Cre-dependent recombinant adenovirus encoding farnesylated enhanced green fluorescent protein into the ARN or RP3V of adult male and female mice expressing Cre recombinase in kisspeptin neurons. Fibers from ARN kisspeptin neurons projected widely; however, we did not find any evidence for direct contact with GnRH neuron somata or proximal dendrites in either sex. In contrast, we identified RP3V kisspeptin fibers in close contact with GnRH neuron somata and dendrites in both sexes. Fibers originating from both the RP3V and ARN were observed in close contact with distal GnRH neuron processes in the ARN and in the lateral and internal aspects of the median eminence. Furthermore, GnRH nerve terminals were found in close contact with the proximal dendrites of ARN kisspeptin neurons in the ARN, and ARN kisspeptin fibers were found contacting RP3V kisspeptin neurons in both sexes. Together these data delineate selective zones of kisspeptin neuron inputs to GnRH neurons and demonstrate complex interconnections between the distinct kisspeptin populations and GnRH neurons.
亲吻素神经元通过直接调节促性腺激素释放激素（GnRH）神经元，在生育调节中发挥着至关重要的作用。然而，这两个功能不同的亲吻素神经元亚群对这一关键调节的相对贡献尚未完全明确。在此，我们采用细胞特异性、病毒介导的示踪方法，分析了源自第三脑室室周吻侧核（RP3V）或弓状核（ARN）的亲吻素神经元的特定投射模式。我们将编码法尼基化增强型绿色荧光蛋白的Cre依赖性重组腺病毒立体定向注射到成年雄性和雌性小鼠的ARN或RP3V中，这些小鼠的亲吻素神经元中表达Cre重组酶。来自ARN亲吻素神经元的纤维广泛投射；然而，我们未发现任何证据表明在任何性别中其与GnRH神经元胞体或近端树突有直接接触。相比之下，我们在两性中均发现RP3V亲吻素纤维与GnRH神经元胞体和树突紧密接触。在ARN以及正中隆起的外侧和内侧，均观察到源自RP3V和ARN的纤维与GnRH神经元的远端突起紧密接触。此外，在ARN中发现GnRH神经末梢与ARN亲吻素神经元的近端树突紧密接触，并且在两性中均发现ARN亲吻素纤维与RP3V亲吻素神经元接触。这些数据共同描绘了亲吻素神经元向GnRH神经元输入的选择性区域，并证明了不同亲吻素群体与GnRH神经元之间存在复杂的相互连接。
