Kiyokawa Yasushi, Tanaka Kazuyuki D, Ishii Akiko, Mikami Kaori, Katayama Masatoshi, Koizumi Ryoko, Minami Syota, Tanikawa Tsutomu, Takeuchi Yukari
Laboratory of Veterinary Ethology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
J Vet Med Sci. 2017 Apr 5;79(4):702-708. doi: 10.1292/jvms.17-0002. Epub 2017 Feb 16.
Wild animals generally avoid even small and harmless novel objects and/or familiar objects moved to a novel position, which is termed "new-object reaction". Although new-object reaction appears to be a biologically important characteristic for animals, little progress has been made in understanding the neural mechanisms underlying new-object reaction. One reason might be the lack of effective experimental animals. Two strains of roof rats (Sj and Og strains) were established from wild roof rats caught in Shinjuku, Tokyo and one of the Ogasawara Islands, respectively, by a Japanese pest control company. Based on the rat caregivers' informal observations, we conducted behavioral and anatomical tests to assess the validity of Sj and Og strains for the analyses of new-object reaction. In Experiment 1, the Sj strain showed reduced food consumption compared with the Og strain when food was provided in a novel way, suggesting that the Sj strain had a stronger avoidance of novel objects compared with the Og strain. Experiment 2 demonstrated that the basolateral complex of the amygdala and bed nucleus of the stria terminalis in experimental Sj rats had a larger percentage area compared with that of experimental Og rats, indicating these nuclei might be involved in the difference observed in avoidance of novel objects between the strains. Taken together, the present study suggests that Sj and Og strains are effective experimental animals for assessing new-object reaction.
野生动物通常会避开即使是小的、无害的新奇物体和/或将熟悉的物体移到新位置，这被称为“新物体反应”。尽管新物体反应似乎是动物的一个生物学上重要的特征，但在理解新物体反应背后的神经机制方面进展甚微。一个原因可能是缺乏有效的实验动物。两种屋顶大鼠品系（Sj和Og品系）分别由一家日本害虫防治公司从东京新宿和小笠原群岛之一捕获的野生屋顶大鼠培育而成。基于大鼠饲养者的非正式观察，我们进行了行为和解剖测试，以评估Sj和Og品系用于分析新物体反应的有效性。在实验1中，当以新的方式提供食物时，Sj品系与Og品系相比食物消耗量减少，这表明Sj品系与Og品系相比对新奇物体有更强的回避反应。实验2表明，实验性Sj大鼠杏仁核的基底外侧复合体和终纹床核的面积百分比与实验性Og大鼠相比更大，表明这些核可能与品系间在回避新奇物体方面观察到的差异有关。综上所述，本研究表明Sj和Og品系是评估新物体反应的有效实验动物。
