Phoenixin is a recently discovered peptide, which has been associated with reproduction, anxiety and food intake. Based on a considerable co-localization it has been linked to nesfatin-1, with a possible antagonistic mode of action. Since nesfatin-1 is known to play a role in anxiety and the response to stress, this study aims to investigate the effects of a well-established psychological stress model, restraint stress, on phoenixin-expressing brain nuclei and phoenixin expression in rats. Male Sprague-Dawley rats were subjected to restraint stress (n=8) or left undisturbed (control, n=6) and the brains processed for c-Fos- and phoenixin immunohistochemistry. The number of c-Fos expressing cells was counted and phoenixin expression assessed semiquantitatively. Restraint stress significantly increased c-Fos expression in the dorsal motor nucleus of vagus nerve (DMN, 52-fold, p < 0.001), raphe pallidus (RPa, 15-fold, p < 0.001), medial part of the nucleus of the solitary tract (mNTS, 16-fold, p < 0.001), central amygdaloid nucleus, medial division (CeM, 9-fold, p = 0.012), supraoptic nucleus (SON, 9-fold, p < 0.001) and the arcuate nucleus (Arc, 2.5-fold, p < 0.03) compared to control animals. Also phoenixin expression significantly increased in the DMN (17-fold, p < 0.001), RPa (2-fold, p < 0.001) and mNTS (1.6-fold, p < 0.001) with positive correlations between c-Fos and phoenixin (r = 0.74-0.85; p < 0.01) in these nuclei. This pattern of activation suggests an involvement of phoenixin in response to restraint stress. Whether phoenixin mediates stress effects or is activated in a counterbalancing fashion will have to be further investigated.

Phoenixin 是最近发现的一种肽，它与生殖、焦虑和食物摄入有关。基于相当大的共定位，它与 nesfatin-1 相关联，可能具有拮抗作用。由于 nesfatin-1 已知在焦虑和对压力的反应中发挥作用，本研究旨在研究成熟的心理压力模型、约束压力对大鼠表达 phoenixin 的脑核和 phoenixin 表达的影响。雄性 Sprague-Dawley 大鼠受到束缚应激 (n=8) 或不受干扰（对照，n=6），并对大脑进行 c-Fos- 和 phoenixin 免疫组织化学处理。对 c-Fos 表达细胞的数量进行计数，并半定量评估凤凰霉素的表达。p < 0.001），苍白中缝（RPa，15 倍，p < 0.001），孤束核的内侧部分（mNTS，16 倍，p < 0.001），中央杏仁核，内侧分裂（CeM，9倍，p = 0.012）、视上核（SON，9 倍，p < 0.001）和弓状核（Arc，2.5 倍，p < 0.03）与对照动物相比。此外，在 DMN（17 倍，p < 0.001）、RPa（2 倍，p < 0.001）和 mNTS（1.6 倍，p < 0.001）中phoenixin 表达显着增加，c-Fos 和 phoenixin 之间呈正相关（r = 0.74-0.85；p < 0.01) 在这些核中。这种激活模式表明凤凰参与了对约束压力的反应。凤凰霉素是否介导压力效应或以平衡方式被激活将必须进一步研究。