The Preoptic Area and the RFamide-Related Peptide Neuronal System Gate Seasonal Changes in Chemosensory Processing
The Preoptic Area and the RFamide-Related Peptide Neuronal System Gate Seasonal Changes in Chemosensory Processing
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DOI：
10.1093/icb/icx099
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发表时间：
2017-11-01
影响因子：
2.6
通讯作者：
Kriegsfeld, Lance J.
中科院分区：
文献类型：
--
作者：
Jennings, Kimberly J.;Chasles, Manon;Kriegsfeld, Lance J.
许多物种的雄性依赖化学感受信息进行社会交流。在雄性叙利亚仓鼠（Mesocricetus auratus）中，与许多物种一样，雌性化学信号强烈刺激性行为，同时快速增加循环中的促黄体生成激素（LH）和睾酮（T）。然而，在冬季一样，短日照（SD）的光周期，当叙利亚仓鼠生殖静止，这些相同的女性化学信号未能引起行为或激素反应，即使在T替代。目前尚不清楚大脑中的化学感受处理以季节性依赖的方式进行门控，使得生殖反应仅在适当的繁殖季节显示。本研究的目的是确定这种门控发生的神经基因座，不同的女性化学信号的光周期，独立的循环T浓度。将成年雄性叙利亚仓鼠圈养在长日照（LD）（生殖活跃）或SD（生殖不活跃）光周期下，其中一半SD动物接受T替代。将动物暴露于用矿物油稀释的雌性仓鼠阴道分泌物（FHVS）或溶剂中，并检查化学感觉处理中心和神经内分泌生殖轴元素的激活状态。下丘脑中心上游的化学感受通路的成分增加了FOS的表达，FOS是神经元活化的间接标志物，在光周期中也是如此。相反，下丘脑视前区（POA）只在LD动物中对FHVS作出反应，这与其在促进雄性性行为表达中的作用一致。在神经内分泌轴，RF-酰胺相关肽（RFRP），但不是kisspeptin神经元系统响应FHVS只在LD动物。在SD动物中，POA或RFRP神经元系统内的反应均未被T替代所拯救，反映了生殖反应的光周期调节。考虑到POA和RFRP神经元系统促进雄性叙利亚仓鼠的生殖行为和功能，这些系统的差异激活代表了一种潜在的手段，通过这种手段，光周期限制了生殖表达到适当的环境背景。
Males of many species rely on chemosensory information for social communication. In male Syrian hamsters (Mesocricetus auratus), as in many species, female chemosignals potently stimulate sexual behavior and a concurrent, rapid increase in circulating luteinizing hormone (LH) and testosterone (T). However, under winter-like, short-day (SD) photoperiods, when Syrian hamsters are reproductively quiescent, these same female chemosignals fail to elicit behavioral or hormonal responses, even after T replacement. It is currently unknown where in the brain chemosensory processing is gated in a seasonally dependent manner such that reproductive responses are only displayed during the appropriate breeding season. The goal of the present study was to determine where this gating occurred by identifying neural loci that respond differentially to female chemosignals across photoperiods, independent of circulating T concentrations. Adult male Syrian hamsters were housed under either long-day (LD) (reproductively active) or SD (reproductively inactive) photoperiods with half of the SD animals receiving T replacement. Animals were exposed to either female hamster vaginal secretions (FHVSs) diluted in mineral oil or to vehicle, and the activational state of chemosensory processing centers and elements of the neuroendocrine reproductive axis were examined. Components of the chemosensory pathway upstream of hypothalamic centers increased expression of FOS, an indirect marker of neuronal activation, similarly across photoperiods. In contrast, the preoptic area (POA) of the hypothalamus responded to FHVS only in LD animals, consistent with its role in promoting expression of male sexual behavior. Within the neuroendocrine axis, the RF-amide related peptide (RFRP), but not the kisspeptin neuronal system responded to FHVS only in LD animals. Neither response within the POA or the RFRP neuronal system was rescued by T replacement in SD animals, mirroring photoperiodic regulation of reproductive responses. Considering the POA and the RFRP neuronal system promote reproductive behavior and function in male Syrian hamsters, differential activation of these systems represents a potential means by which photoperiod limits expression of reproduction to the appropriate environmental context.