Kapoor Amita, Kostaki Alice, Janus Christopher, Matthews Stephen G
Department of Physiology, Faculty of Medicine, University of Toronto, Medical Sciences Building, 1 King's College Circle, Toronto, Ontario, M5S 1A8 Canada.
Behav Brain Res. 2009 Jan 30;197(1):144-9. doi: 10.1016/j.bbr.2008.08.018. Epub 2008 Aug 22.
Impaired fetal development has been linked with deficits in behavioural and emotional development during postnatal life. In order to investigate the mechanisms underlying this relationship, we studied the effect of acute stress at two different critical phases of pregnancy on cognitive function in adult guinea pig offspring. Pregnant guinea pigs were exposed to a psychological stressor (2h/day) on gestational days (gd) 50, 51, and 52 (PS50) or 60, 61, and 62 (PS60). Male offspring were grown to adulthood and tested in the Morris water maze (MWM) to assess spatial learning and memory. Latency, path length, swim speed and the strategy used to find the platform in each session of the MWM were measured. A reverse learning trial was performed where the platform was moved to a different area of the pool and the ability of the guinea pigs to learn a new platform position was assessed. There was no effect of stress at gd50 on latency to find the platform during any of the sessions in the MWM. PS60 male offspring exhibited enhanced development of a spatial strategy during sessions 3 and 4 of the MWM, but this was not associated with decreased latency. In the reversal task PS50 male offspring demonstrated use of non-spatial strategies to find the platform during the reversal task. This would suggest decreased retention of spatial memory in these animals. In contrast, control and PS60 male offspring demonstrated no bias to a particular strategy type. In conclusion, there are subtle effects of prenatal stress on spatial learning. PS60 offspring appear to exhibit enhanced spatial learning, while PS50 male offspring exhibit impaired spatial learning. These findings are consistent with those in humans, which indicate a strong effect of maternal anxiety during pregnancy on cognition in children, and that the timing of the maternal stress is critical to determining outcome. This model will allow us to determine the mechanisms that underlie the association between prenatal stress and altered learning strategy and ability.
胎儿发育受损与出生后行为和情感发育缺陷有关。为了研究这种关系背后的机制，我们研究了孕期两个不同关键阶段的急性应激对成年豚鼠后代认知功能的影响。怀孕的豚鼠在妊娠第50、51和52天（PS50）或第60、61和62天（PS60）每天暴露于心理应激源2小时。雄性后代成长至成年，并在莫里斯水迷宫（MWM）中进行测试，以评估空间学习和记忆能力。测量了在MWM每次试验中找到平台的潜伏期、路径长度、游泳速度以及使用的策略。进行了反向学习试验，将平台移至水池的不同区域，并评估豚鼠学习新平台位置的能力。妊娠第50天的应激对MWM任何试验中找到平台的潜伏期均无影响。PS60雄性后代在MWM的第3和第4次试验中表现出空间策略的增强发展，但这与潜伏期缩短无关。在反向任务中，PS50雄性后代在反向任务中表现出使用非空间策略来寻找平台。这表明这些动物的空间记忆保留减少。相比之下，对照组和PS60雄性后代对特定策略类型没有偏好。总之，产前应激对空间学习有微妙影响。PS60后代似乎表现出增强的空间学习能力，而PS50雄性后代表现出受损的空间学习能力。这些发现与人类的研究结果一致，表明孕期母亲焦虑对儿童认知有强烈影响，且母亲应激的时间对于确定结果至关重要。该模型将使我们能够确定产前应激与学习策略和能力改变之间关联的潜在机制。
