Altman Daniel E, Simmons Laurence P, Vuong Chau T, Taylor Rachel M, Sousa Jason C, Marcsisin Sean R, Zottig Victor E, Moore Nicole L T
a Center for Military Psychiatry and Neuroscience, Department of Behavioral Biology , Walter Reed Army Institute of Research , Silver Spring , MD , USA.
b Division of Experimental Therapeutics, Drug Metabolism and Distribution Branch , Walter Reed Army Institute of Research , Silver Spring , MD , USA.
Stress. 2018 May;21(3):267-273. doi: 10.1080/10253890.2018.1439012. Epub 2018 Feb 16.
Adolescence is a distinct developmental period characterized by behavioral and physiological maturation. Rapid ongoing changes during neurodevelopment in particular present potential opportunities for stress to have lasting effects on longitudinal outcomes of behavioral and neuroendocrine function. While adult stress effects on outcomes during adulthood have been characterized, little is known about the lasting effects of adolescent repeated stressor exposure on outcomes during adolescence. We have previously reported different stress responses in adolescent rats relative to adult rats, including a blunted fear response outcome in adulthood in rats stressed during adolescence. The present study characterized the ontogeny of behavioral and neuroendocrine responses to eight underwater trauma (UWT) exposures in rats over a two week poststress time period during adolescence (P34) or adulthood (P83) relative to age-matched control groups that underwent eight swimming episodes without UWT. Repeated UWT exposures starting in adolescence, but not adulthood, resulted in adverse behavioral responses on the elevated plus maze 1 day post-stress. Corticosterone responses did not differ between UWT-exposed and controls for either age group at 1 day or at 7 days poststress, although there was an effect of age on corticosterone levels. We conclude that repeated UWT stress events have a lasting, negative behavioral effect on adolescent rats that is not observed in adult rats after the two-week exposure window. These results suggest that neurophysiological mechanisms underlying recovery from a repeated stressor are immature in adolescence relative to adulthood in rats.
青春期是一个独特的发育阶段，其特征是行为和生理成熟。神经发育过程中持续快速的变化尤其为压力对行为和神经内分泌功能的纵向结果产生持久影响提供了潜在机会。虽然成年期压力对成年期结果的影响已得到描述，但对于青少年反复暴露于应激源对青少年期结果的持久影响知之甚少。我们之前报道过，与成年大鼠相比，青春期大鼠有不同的应激反应，包括在青春期受到应激的大鼠成年后恐惧反应结果减弱。本研究描述了在青春期（P34）或成年期（P83）的应激后两周时间内，相对于经历八次无水下创伤（UWT）游泳事件的年龄匹配对照组，大鼠对八次水下创伤（UWT）暴露的行为和神经内分泌反应的个体发生情况。从青春期而非成年期开始反复暴露于UWT，会在应激后1天对高架十字迷宫产生不良行为反应。应激后1天或7天，UWT暴露组和对照组的皮质酮反应在两个年龄组中均无差异，尽管年龄对皮质酮水平有影响。我们得出结论，反复的UWT应激事件对青春期大鼠有持久的负面行为影响，而成年大鼠在两周的暴露窗口后未观察到这种影响。这些结果表明，相对于成年大鼠，青春期大鼠从反复应激源中恢复的神经生理机制尚不成熟。
