Haemisch A, Voss T, Gärtner K
Department of Laboratory Animal, Medical School Hannover, Germany.
Physiol Behav. 1994 Nov;56(5):1041-8. doi: 10.1016/0031-9384(94)90341-7.
Adult male mice (DBA/2J) siblings were housed three per cage for 6 wk, either in standard cages (SC) or in enriched cages (EC). Both attacks among group members and attacks against strange intruders were monitored once a week within each of 22 experimental groups. According to its attacking behavior, each mouse was categorized into one of three dominance categories: dominant, subdominant active, subdominant passive. Aggressive behavior and social organization were compared between the two types of housing conditions, and the effects of housing condition and dominance category on endocrinological and some organometrical parameters were analysed. The main findings were: (a) Mice in EC attacked intruders significantly more frequently compared to mice in SC; (b) In EC groups the position of the dominant male was less stable than in SC groups; (c) Plasma corticosterone titers (PCT) were significantly elevated in EC. Activities of tyrosinehydroxylase (TH) and phenylethanolamine-N-methyltransferase (PNMT) did not differ significantly between the housing conditions; (d) TH and PNMT activity were significantly enhanced in the dominant males of SC groups compared to subdominant passive males. Intermediate activities for both enzymes were determined for subdominant active males; and (e) PCT were significantly elevated in dominant males of the EC groups compared to subdominant active and subdominant passive males and also compared to the dominant males in the SC groups. Findings suggest that keeping adult male mice in structured cages can result in increased aggression towards intruders, a change in the social organization, and altered endocrine states, depending on the individual dominance position.
成年雄性小鼠（DBA/2J）同胞每笼饲养3只，为期6周，饲养在标准笼（SC）或丰富笼（EC）中。在22个实验组中，每周对每个组内成员之间的攻击以及对陌生入侵者的攻击进行一次监测。根据其攻击行为，每只小鼠被分为三个优势类别之一：优势、次优势活跃、次优势被动。比较了两种饲养条件下的攻击行为和社会组织，并分析了饲养条件和优势类别对内分泌和一些器官测量参数的影响。主要发现如下：（a）与饲养在SC中的小鼠相比，饲养在EC中的小鼠对入侵者的攻击频率显著更高；（b）在EC组中，优势雄性的地位比SC组中更不稳定；（c）EC组的血浆皮质酮水平（PCT）显著升高。两种饲养条件下酪氨酸羟化酶（TH）和苯乙醇胺-N-甲基转移酶（PNMT）的活性没有显著差异；（d）与次优势被动雄性相比，SC组优势雄性的TH和PNMT活性显著增强。次优势活跃雄性的这两种酶活性处于中间水平；（e）与次优势活跃和次优势被动雄性相比，以及与SC组的优势雄性相比，EC组优势雄性的PCT显著升高。研究结果表明，将成年雄性小鼠饲养在结构化笼子中会导致对入侵者的攻击性增加、社会组织的变化以及内分泌状态的改变，这取决于个体的优势地位。
