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

为了研究新肽松弛素3（RLN 3）的功能，我们制作了基因敲除小鼠，并进行了一系列的行为学测试。RLN 3 KO小鼠表现出正常的生长和外观，并且通常与野生基因型同窝仔难以区分。各基因型间体重差异不显著。然而，KO小鼠在高架十字迷宫测试中表现出进入开放臂的趋势的稳健增加。因此，相对于野生型小鼠，RLN 3 KO小鼠表现出轻度抗焦虑特征，表明该肽参与焦虑相关行为（Watanabe Y等人，Front Behav Neurosci 2011）。我们还研究了RLN 3的下丘脑作用的应激反应系统，通过将其注入脑室。与生理盐水注射相比，侧脑室注射1 nmol RLN 3后，下丘脑室旁核（PVN）c-Fos表达增加。在含CRF的神经元中，PVN前部的部分c-Fos被诱导。RLN 3给药后15分钟血浆ACTH水平也增加。这些结果表明，RLN 3能够刺激下丘脑-垂体CRF-ACTH系统，其在急性期响应于外部应激（Watanabe Y等人，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了RLN 3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).