中文摘要：

最近基因组研究表明树鼩属于灵长类或是与灵长类亲缘关系最密切的姐妹种。因此, 树鼩可能是应用于建立人类疾病动物模型的最佳动物之一。该文报道一种抑郁症的社会竞争失败病因学树鼩 （Tupaia belangeri chinensis）模型。一对雄性树鼩被饲养在一个双笼中, 用网格把双笼隔开, 网格上有一小门。适应1周后, 把小门打开, 这一对树鼩产生短暂的争斗, 每天一次,连续21天。其中争斗失败者被称为服从者。这个过程可导致每天1h的直接社交冲突和23h的间接相互影响 （比如通过气味、视觉等）。与正常对照相比, 失败者在第三周也就是社交冲突的最后一周显示了体重、自主活动、躲避行为、尿液皮质醇水平等的变化, 并且这种改变可持续至少2周以上。此外, 还报道全新的记忆模型, 一种被捕获条件反射树鼩模型。在一个封闭的小房间中放置捕获笼, 其中挂有一片苹果, 小房间中有一只自由活动的树鼩。训练的前4次树鼩进入捕获笼吃苹果并不触发捕获笼关闭, 但在第5次时触发捕获笼关闭, 并持续一小时才释放树鼩。第1—5 次树鼩进入捕获笼的延迟时间作为适应性指标, 其中第5次才是作为被捕获的一次学习训练。24h后, 测试树鼩进入捕获笼的延迟时间作为被捕获记忆能力指标。树鼩经过第5次被捕获训练, 能形成很好的被捕获记忆, 因为24h后的延迟时间极大地增加。在训练前腹腔注射已知能阻断记忆形成的 NMDA受体拮抗剂MK-801（0.2mg/kg, 腹腔注射）, 对适应指标没有显著影响, 但是极大地缩短了24h后测试的延迟时间, 即阻断了被捕获记忆。这些结果表明了一种抑郁症的慢性社会竞争失败与学习和记忆的一次被捕获条件反射树鼩模型。这两种树鼩模型对抑郁症与学习和记忆的机理研究、抗抑郁症新药的临床前药效学评价具有潜在的重要意义。

英文摘要：

Recent genome studies indicate that tree shrew is in the order or a closest sister of primates,and thus may be one of the best animals to model human diseases.In this paper,we report on a social defeat model of depression in tree shrew（Tupaia belangeri chinensis）.Two male tree shrews were housed in a pair-cage consisting of two independent cages separated by a wire mesh partition with a door connecting the two cages.After one week adaptation,the connecting door was opened and a brief fighting occurs between the two male tree shrews and this social conflict session consisted of 1 h direct conflict（fighting） and 23 h indirect influence（e.g.smell,visual cues） per day for 21 days.The defeated tree shrew was considered the subordinate.Compared with na？ve animals,subordinate tree shrews at the final week of social conflict session showed alterations in body weight,locomotion,avoidance behavior and urinary cortisol levels.Remarkably,these alterations persisted for over two weeks.We also report on a novel captive conditioning model of learning and memory in tree shrew.An automatic trapping cage was placed in a small closed room with a freely-moving tree shrew.For the first four trials,the tree shrew was not trapped when it entered the cage and ate the bait apple,but it was trapped and kept in the cage for 1 h on the fifth trial.Latency was defined as the time between release of the tree shrew and when it entered the captive cage.Latencies during the five trials indicated adaptation.A test trial 24 h later was used to measure whether the one-trial trapping during the fifth trial could form captive memory.Tree shrews showed much longer trapping latencies in the test trial than the adaptation trials.The N-methyl-d-aspartate（NMDA） receptor antagonist MK-801（0.2 mg/kg,i.p.）,known to prevent the formation of memory,did not affect latencies in the adaptation trails,but did block captive memory as it led to much shorter trapping latencies compared to saline treatment in the test trial.These results demonstr