Wongwitdecha N, Marsden C A
Department of Physiology and Pharmacology, University of Nottingham Medical School, Queen's Medical Center, UK.
Behav Brain Res. 1996 Feb;75(1-2):27-32. doi: 10.1016/0166-4328(96)00181-7.
Isolation rearing in the early stages of life has been shown to modify a variety of behaviours in many animals and the responsitivity to psychotropic drugs. The aims of the present study were to investigate the effects of isolation rearing on anxiety using the social interaction paradigm and to compare the effects of diazepam on social interaction behaviours in isolation and socially reared rats. Male Lister hooded rats were reared from weaning either alone (isolation reared) or in groups of four (socially reared) for 6 weeks and then were tested for social interaction. Both isolation and socially reared rats were exposed to the social interaction test either without drug treatment or following saline or diazepam (1 and 2.5 mg/kg, i.p., 30 min before testing). The results demonstrate that under high light in an unfamiliar arena, the isolation compared to the socially reared rats showed a significantly (P < 0.01) higher level of social interaction, manifested as increases in aggressive and avoidance behaviours, and that this interaction occur for a greater length of time during the test period (10 min). However, when the light level was decreased or when the arena was familiar, active social interaction of isolation reared rats decreased but increased in the socially reared rats. In both conditions the isolation reared rats displayed more aggressive behaviours, in particular biting and boxing the partners which did not occur with the socially reared rats. Pretreatment of diazepam (1 and 2.5 mg/kg., i.p.) caused a dose-related reduction in aggressive behaviours in rats reared under both conditions but increased passive interactions in the socially reared rats. In contrast diazepam (2.5 mg/kg) reduced active interaction in the isolation reared rats but had no effect on passive interaction. These results indicate that isolation rearing increases aggressive behaviours and alters the effects of diazepam.
研究表明，生命早期阶段的隔离饲养会改变许多动物的多种行为以及对精神药物的反应性。本研究的目的是使用社会互动范式研究隔离饲养对焦虑的影响，并比较地西泮对隔离饲养和群居饲养大鼠社会互动行为的影响。雄性利斯特戴帽大鼠从断奶后开始，要么单独饲养（隔离饲养），要么以四只一组的方式饲养（群居饲养），持续6周，然后进行社会互动测试。隔离饲养和群居饲养的大鼠在未接受药物治疗、接受生理盐水或地西泮（1和2.5毫克/千克，腹腔注射，测试前30分钟）后，均接受社会互动测试。结果表明，在陌生环境的强光下，与群居饲养的大鼠相比，隔离饲养的大鼠表现出显著更高水平（P < 0.01）的社会互动，表现为攻击和回避行为增加，并且这种互动在测试期（10分钟）内持续更长时间。然而，当光照水平降低或环境熟悉时，隔离饲养大鼠的积极社会互动减少，而群居饲养大鼠的积极社会互动增加。在这两种情况下，隔离饲养的大鼠表现出更多的攻击行为，特别是咬和拳击同伴，而群居饲养的大鼠则不会出现这种情况。地西泮预处理（1和2.5毫克/千克，腹腔注射）导致两种饲养条件下的大鼠攻击行为均出现剂量相关的减少，但群居饲养的大鼠被动互动增加。相比之下，地西泮（2.5毫克/千克）减少了隔离饲养大鼠的主动互动，但对被动互动没有影响。这些结果表明，隔离饲养会增加攻击行为并改变地西泮的作用。
