Department of Biological Sciences, Stanford University, Stanford, CA, 94305, USA.
Department of Basic Psychological Processes and their Development, Basque Country University, San Sebastián, 20018, Spain.
Mol Psychiatry. 2019 Aug;24(8):1178-1188. doi: 10.1038/s41380-017-0013-1. Epub 2018 Jan 8.
Chronic stress is a recognized risk factor for psychiatric and psychological disorders and a potent modulator of adult neurogenesis. Numerous studies have shown that during stress, neurogenesis decreases; however, during the recovery from the stress, neurogenesis increases. Despite the increased number of neurons born after stress, it is unknown if the function and morphology of those neurons are altered. Here we asked whether neurons in adult mice, born during the final 5 days of chronic social stress and matured during recovery from chronic social stress, are similar to neurons born with no stress conditions from a quantitative, functional and morphological perspective, and whether those neurons are uniquely adapted to respond to a subsequent stressful challenge. We observed an increased number of newborn neurons incorporated in the dentate gyrus of the hippocampus during the 10-week post-stress recovery phase. Interestingly, those new neurons were more responsive to subsequent chronic stress, as they showed more of a stress-induced decrease in spine density and branching nodes than in neurons born during a non-stress period. Our results replicate findings that the neuronal survival and incorporation of neurons in the adult dentate gyrus increases after chronic stress and suggest that such neurons are uniquely adapted in the response to future social stressors. This finding provides a potential mechanism for some of the long-term hippocampal effects of stress.
慢性应激是精神和心理障碍的公认风险因素，也是成年神经发生的有效调节剂。大量研究表明，在应激期间，神经发生减少；然而，在应激恢复期间，神经发生增加。尽管应激后产生的神经元数量增加，但尚不清楚这些神经元的功能和形态是否发生改变。在这里，我们想知道成年小鼠在慢性社交应激的最后 5 天中产生的神经元，以及在慢性社交应激恢复期间成熟的神经元，是否从数量、功能和形态学角度来看与没有应激条件下产生的神经元相似，以及这些神经元是否独特地适应于应对随后的应激挑战。我们观察到在应激后 10 周的恢复阶段，海马齿状回中新生神经元的数量增加。有趣的是，这些新神经元对随后的慢性应激更为敏感，因为它们的棘突密度和分支节点的应激诱导减少比在非应激期产生的神经元更为明显。我们的研究结果复制了慢性应激后成年海马齿状回中神经元存活和新生神经元数量增加的发现，并表明这些神经元在应对未来社会应激源方面具有独特的适应性。这一发现为应激对海马体的一些长期影响提供了潜在的机制。
