Department of Neurology, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Zhongshan Hospital, Fudan University, Shanghai 200032, China.
The Department of Anesthesia and Pain, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou 310006, China; Department of Anesthesia, The Fifth People's Hospital of Shanghai, Fudan University, Shanghai, China.
Neuroscience. 2019 Sep 1;415:18-30. doi: 10.1016/j.neuroscience.2019.07.018. Epub 2019 Jul 17.
Previous studies have focused on the effects of N-methyl-D-aspartate receptor (NMDAR) blockade on neonates, but little is known about the effect of the embryonic NMDAR blockade on offspring, especially the long-lasting effect, on behavior in adulthood. Here, pregnant rats at E14 were treated with ketamine for 5 successive days and undergone multiple behavior tests, electrophysiology experiment, and Western blotting analysis to detect the alterations in their offspring. We found that embryonic ketamine treatment induced anxiety-like behavior in adulthood (8-week old) offspring. At the same period, we observed an attenuation of NMDA-evoked current as well as decreased NR2A and NR2B membrane expression in the prefrontal cortex (PFC), but not in the hippocampus or amygdala. Selective inhibition experiments with NR2A or NR2B specific antagonists suggested that embryonic ketamine treatment induced NMDAR current attenuation was likely mediated by changes in NR2A subunit. Moreover, at the 4-week time point, NMDA-evoked current was unchanged in PFC, but enhanced in hippocampal CA1 area, which may be caused by the over expression of NR2B in the hippocampus at 4-week time. Furthermore, NR2B knockdown, by using NR2B-shRNA lentivirus, in the hippocampal CA1 area at 3-4-week of age significantly rescued the decrease in NR2A expression in the PFC and anxiety-like behavior observed at 8-week adult offspring rats. In conclusion, our results suggested that embryonic ketamine treatment induced anxiety-like behavior and the downregulation of NMDAR function in PFC in the adulthood period of offspring, which might result from the enhanced function of NMDARs in the hippocampus at the 4-week juvenile time point.
先前的研究集中在 N-甲基-D-天冬氨酸受体 (NMDAR) 阻断对新生儿的影响上，但对于胚胎 NMDAR 阻断对后代的影响，尤其是对成年后行为的长期影响，知之甚少。在这里，妊娠第 14 天的大鼠连续 5 天用氯胺酮处理，并进行多项行为测试、电生理实验和 Western blot 分析，以检测其后代的变化。我们发现胚胎期氯胺酮处理会导致成年（8 周龄）后代出现类似焦虑的行为。同期，我们观察到前额叶皮质（PFC）中 NMDA 诱发电流减弱以及 NR2A 和 NR2B 膜表达减少，但海马体或杏仁核中没有。使用 NR2A 或 NR2B 特异性拮抗剂的选择性抑制实验表明，胚胎期氯胺酮处理诱导的 NMDAR 电流减弱可能是由 NR2A 亚基的变化介导的。此外，在 4 周时，PFC 中的 NMDA 诱发电流没有变化，但海马 CA1 区的增强，这可能是由于海马体在 4 周时 NR2B 的过度表达引起的。此外，在 3-4 周龄时，通过使用 NR2B-shRNA 慢病毒在海马 CA1 区敲低 NR2B，可显著挽救 PFC 中 NR2A 表达减少和成年期 8 周龄后代大鼠观察到的类似焦虑行为。总之，我们的结果表明，胚胎期氯胺酮处理会导致成年后代出现类似焦虑的行为和 PFC 中 NMDAR 功能下调，这可能是由于海马体在 4 周龄幼年期时 NMDAR 功能增强所致。
