Ferris Craig F, Messenger Tara, Sullivan Ross
Center for Comparative Neuroimaging, University of Massachusetts Medical School, Worcester, Massachusetts, USA.
Front Zool. 2005 Apr 22;2(1):7. doi: 10.1186/1742-9994-2-7.
Social subjugation is a very significant and natural stressor in the animal kingdom. Adult animals defeated and subjugated during establishment of dominance hierarchies or territorial encounters can be highly submissive in future agonistic interactions. While much is know about the biological and behavioral consequences of winning and losing fights in adulthood, little is known about adolescence; a developmental period noted for impulsivity and heightened agonistic behavior. The present studies were undertaken to determine if the behavioral and neuroendocrine consequences of social subjugation are comparable in adolescent versus adult Syrian golden hamsters (Mesocricetus auratus). Male siblings were studied from adolescence into adulthood following exposure to counterbalanced episodes of either a benign stressor, i.e., isolation in a novel cage, or the more severe stressor of social subjugation. RESULTS: As adults, hamsters with a history of social subjugation in adolescence show high levels of aggression toward intruders as compared to siblings subjugated in adulthood. Sibling controls subjugated in adulthood are highly submissive with little or no aggressive behavior. However, when subjugated in adulthood, hamsters with the earlier history of subjugation are no different than their sibling controls, i.e., adult subjugation promotes submissive behavior. Sexual motivation is high in adult hamsters with adolescent subjugation and testosterone levels remained stable over adulthood. In contrast, sibling controls subjugated in adulthood show lower levels of sexual motivation and reduced levels of testosterone. Release of cortisol during agonistic encounters is blunted in animals subjugated in adolescence but not adulthood. Measures of anxiety are reduced in hamsters with adolescent subjugation as compared to their sibling controls. CONCLUSION: These data demonstrate a pronounced difference in behavior and neuroendocrinology between adolescent and adult hamsters in their response to social subjugation and suggest adolescence is a resilient period in development.
社会征服是动物王国中一个非常重要且自然的应激源。在优势等级制度建立或领地争夺中被击败并征服的成年动物，在未来的争斗互动中可能会表现出高度顺从。虽然我们对成年动物输赢争斗的生物学和行为后果了解很多，但对于青春期这个以冲动和争斗行为加剧为特征的发育阶段却知之甚少。本研究旨在确定社会征服对青少年和成年叙利亚金黄地鼠（Mesocricetus auratus）行为和神经内分泌的影响是否具有可比性。雄性同胞从青春期到成年期进行研究，在此期间它们经历了良性应激源（即在新笼子中隔离）或更严重的社会征服应激源的平衡处理。结果：成年后，与成年期被征服的同胞相比，青春期有社会征服史的仓鼠对入侵者表现出高度攻击性。成年期被征服的同胞对照则高度顺从，几乎没有或没有攻击行为。然而，成年期被征服时，早期有征服史的仓鼠与它们的同胞对照没有差异，即成年期的征服会促进顺从行为。青春期被征服的成年仓鼠性动机较高，且睾酮水平在成年期保持稳定。相比之下，成年期被征服的同胞对照性动机较低，睾酮水平也降低。在争斗互动中，青春期被征服的动物皮质醇释放受到抑制，而成年期被征服的动物则没有。与它们的同胞对照相比，青春期被征服的仓鼠焦虑水平降低。结论：这些数据表明，青少年和成年仓鼠在对社会征服的反应中，行为和神经内分泌存在明显差异，这表明青春期是一个发育中的弹性时期。
