Abstract：
To understand better the role that kisspeptin plays in regulating seasonal and estrous cycle changes in the mare, this study investigated the number, location and interactions between GnRH, kisspeptin and RFRP-3 neurons in the equine hypothalamus. Hypothalami were collected from mares during the non-breeding season, vernal transition and various stages of the breeding season. Fluorescent immunohistochemistry was used to label the neuropeptides of interest. GnRH cells were observed primarily in the arcuate nucleus (ARC), while very few labeled cells were identified in the pre-optic area (POA). Kisspeptin cells were identified primarily in the ARC, with a small number of cells observed dorsal to the ARC, surrounding the third ventricle (3V). The mean number of kisspeptin cells varied between animals and typically showed no pattern associated with season or stage of estrous cycle, but a seasonal difference was identified in the ARC population. Small numbers of RFRP-3 cells were observed in the ARC, ventromedial hypothalamus (VMH) and dorsomedial hypothalamus (DMH). The mean number of RFRP-3 cells appeared higher in pre-ovulatory animals compared to all other stages. The percentage of GnRH cell bodies with kisspeptin appositions did not change with season or stage of estrous cycle. The percentage of kisspeptin cells receiving inputs from RFRP-3 fibers did not vary with season or stage of estrous cycle. These interactions suggest the possibility of the presence of an ultra-short loop feedback system between these three peptides. The changes in RFRP-3 neurons suggest the possibility of a role in the regulation of reproduction in the horse, but it is unlikely to be as a gonadotropin inhibitory factor.
摘要：
为了更好地了解kisspeptin在调节母马季节和发情周期变化中的作用，这项研究调查了这个数字，GnRH之间的位置和相互作用，马下丘脑中的kisspeptin和RFRP-3神经元。下丘脑是在非繁殖季节从母马中收集的，春季过渡和繁殖季节的各个阶段。使用荧光免疫组织化学标记感兴趣的神经肽。GnRH细胞主要在弓状核（ARC）中观察到，而在前视区（POA）中发现的标记细胞很少。Kisspeptin细胞主要在ARC中被鉴定，在ARC背侧观察到少量细胞，围绕第三脑室（3V）。kisspeptin细胞的平均数量在动物之间有所不同，通常没有表现出与发情周期的季节或阶段相关的模式，但是在ARC人群中发现了季节性差异。在ARC中观察到少量的RFRP-3细胞，腹内侧下丘脑（VMH）和背内侧下丘脑（DMH）。与所有其他阶段相比，排卵前动物中RFRP-3细胞的平均数量似乎更高。具有kisspeptin并置的GnRH细胞体的百分比不随发情周期的季节或阶段而变化。接受RFRP-3纤维输入的kisspeptin细胞的百分比不随发情周期的季节或阶段而变化。这些相互作用表明在这三种肽之间存在超短环反馈系统的可能性。RFRP-3神经元的变化表明在马的繁殖调节中起作用的可能性，但它不太可能作为促性腺激素抑制因子。
