Cirulli F, Terranova M L, Laviola G
Section of Behavioral Pathophysiology, Istituto Superiore di Sanità, Roma, Italy.
Pharmacol Biochem Behav. 1996 May;54(1):99-105. doi: 10.1016/0091-3057(95)02169-8.
The aim of this study was to investigate whether the social relationship between periadolescent rats, which is characterized by a high expression of play behavior, resembles attachment or whether it reflects a nonspecific social attraction between peers. Sprague-Dawley rats have been kept in pairs with a conspecific of the same age and sex from the time of weaning (PND 21). On PND 34, the members of each pair were separated for a 24-h period and randomly assigned to one of three groups: a) immediately sacrificed (NT = nontreated); b) reunited for 30 min with their previous cagemate (FAM); or c) with an unfamiliar conspecific of the same age and sex (UNF). During the reunion, the occurrence of both social and nonsocial behaviors was scored. Overall, periadolescent UNF animals spent more time in social investigation than FAM rats, which were conversely more involved in cage-oriented activities. In addition, higher levels of rough-and-tumble play were expressed in encounters between UNF subjects than between FAM rats. Finally, within the female group, UNF rats were more involved in play soliciting and less in digging activity than FAM animals. Blood corticosterone levels, which were measured at the end of the separation period, were higher in females than in males and were significantly lower than following reunion in a novel environment. The degree of familiarity did not affect hormonal changes. Results suggest that periadolescent rats do not form attachment relationships with each other. However, partner familiarity appears to be an important variable affecting social relationships.
本研究的目的是调查以玩耍行为高表达为特征的青春期前后大鼠之间的社会关系是类似于依恋关系，还是反映了同伴之间非特异性的社会吸引力。从断奶时（出生后第21天）起，将斯普拉格-道利大鼠与年龄和性别相同的同种动物成对饲养。在出生后第34天，将每对大鼠分开24小时，然后随机分为三组之一：a）立即处死（NT = 未处理）；b）与之前的同笼伙伴重聚30分钟（FAM）；或c）与年龄和性别相同的陌生同种动物在一起（UNF）。在重聚期间，对社会行为和非社会行为的发生情况进行评分。总体而言，青春期前后的UNF组动物用于社会探究的时间比FAM组大鼠更多，相反，FAM组大鼠更多地参与以笼子为导向的活动。此外，UNF组大鼠之间的打闹玩耍水平高于FAM组大鼠。最后，在雌性组中，UNF组大鼠比FAM组动物更多地参与玩耍邀请，而挖掘活动则较少。在分离期结束时测量的血液皮质酮水平，雌性高于雄性，且明显低于在新环境中重聚后。熟悉程度并未影响激素变化。结果表明，青春期前后的大鼠之间不会形成依恋关系。然而，伙伴熟悉度似乎是影响社会关系的一个重要变量。
