Functional morphology of neuropeptide RLN3-survey for the involvement in emotion and food intake-

为了研究新肽松弛素-3（RLN3）的功能，我们制作了基因敲除小鼠，并进行了一系列的行为测试。RLN3 KO小鼠表现出正常的生长和外观，与野生基因型的幼崽一般无法区分。各基因型间体重无差异。然而，KO小鼠在升高+迷宫测试中表现出明显的进入张开双臂的倾向。因此，与野生型小鼠相比，RLN3 KO小鼠表现出轻微的抗焦虑特征，这表明该肽参与了焦虑相关行为（Watanabe Y et al, Front Behav Neurosci 2011）。我们还通过将RLN3注入脑室来研究RLN3对下丘脑应激反应系统的作用。与生理盐水相比，注射1nmol icv后RLN3诱导下丘脑室旁核（PVN）中c-Fos的表达量增加。在含CRF的神经元中，部分前PVN的c-Fos被诱导。给药15 min后血浆ACTH水平升高。这些结果表明RLN3能够刺激急性期响应外部应激的下丘脑-垂体CRF-ACTH系统（Watanabe Y et al, J Mol Neurosci 2011）。我写了一篇综述文章，从应激和食物摄入的角度总结RLN3的功能（Tanaka M, FEBS J, 2010）。

In order to investigate the function of newly peptide relaxin-3(RLN3), we have made gene knockout mice and examined a battery of the behavioral tests. RLN3 KO mice exhibited normal growth and appearance, and were generally indistinguishable from wild genotype littermates. There was no difference in bodyweight among genotypes. However, KO mice exhibited a robust increase in the tendency to enter open arms in the elevated plus maze test. Thus RLN3 KO mice exhibit mild anxiolytic characteristics relative to wild-type mice, suggesting that this peptide is involved in anxiety-related behavior(Watanabe Y et al, Front Behav Neurosci 2011). We also investigated the hypothalamic action of RLN3 to stress-responding system by administrating it into the cerebral ventricle. RLN3 induced larger number of c-Fos expressions in the paraventricular nucleus of the hypothalamus(PVN) after 1nmol icv injection compared with saline injection. A part of c-Fos in the anterior PVN was induced in the CRF containing neurons. Plasma ACTH level was also increased 15 min after RLN3 administration. These results suggest that RLN3 is able to stimulate hypothalamo-pituitary CRF-ACTH system which responds to external stress in acute phase(Watanabe Y et al, J Mol Neurosci 2011). I wrote a review article to summarize the function of RLN3 in the view of stress and food intake(Tanaka M, FEBS J, 2010).