Department of Anesthesiology, The First Affiliated Hospital, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China.
Department of Anesthesiology, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China.
Transl Psychiatry. 2020 Jun 20;10(1):202. doi: 10.1038/s41398-020-00884-5.
Sevoflurane, in particular multiple exposures, has been reported to cause the abnormal neurological development including attention-deficit/hyperactivity disorder (ADHD). This study is to investigate ADHD-like impulsivity in adult mice after repeated sevoflurane exposures at the neonatal stage. Six-day-old pups were exposed to 60% oxygen in the presence or absence of 3% sevoflurane for 2 h and the treatment was administrated once daily for three consecutive days. To assess the impulsivity, the cliff avoidance reaction (CAR) was carried out at the 8th week. Our results showed that repeated sevoflurane treatment increased the number of jumps and shortened the jumping latency in the CAR test. The cortices were harvested for immunostaining to detect c-Fos and calmodulin-dependent protein kinase IIα (CaMKIIα) expression in the medial prefrontal cortex (mPFC). We found that mPFC neurons, especially excitatory neurons, were highly activated and related to impulsive behavior. The activation viruses (AAV-CaMKIIα-hM3Dq) were injected to evaluate the effects of specific activation of mPFC excitatory neurons on impulsive behavior in the presence of clozapine-N-oxide (CNO). Likewise, the inhibitory viruses (AAV-CaMKIIα-hM4Di) were injected in the sevoflurane group to explore whether the mPFC excitatory neuronal inhibition reduced the impulsivity. Our results revealed that chemogenetic activation of mPFC excitatory neurons induced impulsive behavior whereas inhibition of mPFC excitatory neurons partially rescued the deficit. These results indicate that repeated sevoflurane exposures at the critical time induce impulsive behavior accompanied with overactivation of mPFC excitatory neurons in adult stages. This work may further extend to understand the ADHD-like impulsive behavior of the anesthetic neurotoxicity.
七氟醚,特别是多次暴露,已被报道可导致包括注意力缺陷/多动障碍(ADHD)在内的神经发育异常。本研究旨在探讨新生期重复七氟醚暴露后成年小鼠是否存在类似 ADHD 的冲动行为。将 6 天大的幼鼠暴露于 60%氧气中,同时存在或不存在 3%七氟醚,每天处理一次,连续 3 天。为了评估冲动行为,在第 8 周进行了悬崖回避反应(CAR)测试。结果显示,重复七氟醚处理增加了 CAR 测试中的跳跃次数并缩短了跳跃潜伏期。采集皮质组织进行免疫染色,以检测内侧前额叶皮质(mPFC)中 c-Fos 和钙调蛋白依赖性蛋白激酶 IIα(CaMKIIα)的表达。结果发现,mPFC 神经元,特别是兴奋性神经元,高度激活,与冲动行为有关。然后注射激活病毒(AAV-CaMKIIα-hM3Dq),以评估在氯氮平-N-氧化物(CNO)存在下特异性激活 mPFC 兴奋性神经元对冲动行为的影响。同样,在七氟醚组中注射抑制性病毒(AAV-CaMKIIα-hM4Di),以探索 mPFC 兴奋性神经元抑制是否可减少冲动行为。结果表明,mPFC 兴奋性神经元的化学遗传激活可诱导冲动行为,而 mPFC 兴奋性神经元的抑制可部分挽救冲动行为缺陷。这些结果表明,在关键时期重复暴露于七氟醚可导致成年期冲动行为,同时 mPFC 兴奋性神经元过度激活。本工作可能进一步扩展到理解麻醉神经毒性的类似 ADHD 的冲动行为。