Background: Monochromatic blue light (MBL), with a wavelength between 400-490 nm, can regulate non-image-forming (NIF) functions of light in the central nervous system. The suprachiasmatic nucleus (SCN) in the brain is involved in the arousal-promoting response to blue light in mice. Animal and human studies showed that the responsiveness of the brain to visual stimuli is partly preserved under general anesthesia. Therefore, this study aimed to investigate whether MBL promotes arousal from sevoflurane anesthesia via activation of the SCN in mice. Methods: The induction and emergence time of sevoflurane anesthesia under MBL (460 nm and 800 lux) exposure was measured. Cortical electroencephalograms (EEGs) were recorded and the burst-suppression ratio (BSR) was calculated under MBL during sevoflurane anesthesia. The EEGs and local field potential (LFP) recordings with or without locally electrolytic ablated bilateral SCN were used to further explore the role of SCN in the arousal-promoting effect of MBL under sevoflurane anesthesia. Immunofluorescent staining of c-Fos was conducted to reveal the possible downstream mechanism of SCN activation. Results: Unlike the lack of effect on the induction time, MBL shortened the emergence time and the EEG recordings showed cortical arousal during the recovery period. MBL resulted in a significant decrease in BSR and a marked increase in EEG power at all frequency bands except for the spindle band during 2.5% sevoflurane anesthesia. MBL exposure under sevoflurane anesthesia enhances the neuronal activity of the SCN. These responses to MBL were abolished in SCN lesioned (SCNx) mice. MBL evoked a high level of c-Fos expression in the prefrontal cortex (PFC) and lateral hypothalamus (LH) compared to polychromatic white light (PWL) under sevoflurane anesthesia, while it exerted no effect on c-Fos expression in the ventrolateral preoptic area (VLPO) and locus coeruleus (LC) c-Fos expression. Conclusions: MBL promotes behavioral and electroencephalographic arousal from sevoflurane anesthesia via the activation of the SCN and its associated downstream wake-related nuclei. The clinical implications of this study warrant further study.

中文翻译：

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单色蓝光激活视交叉上核神经元活动并促进七氟烷麻醉下小鼠的觉醒。

背景：波长在 400-490 nm 之间的单色蓝光 (MBL) 可以调节光在中枢神经系统中的非成像 (NIF) 功能。大脑中的视交叉上核 (SCN) 参与小鼠对蓝光的唤醒促进反应。动物和人类研究表明，大脑对视觉刺激的反应在全身麻醉下部分保留。因此，本研究旨在研究 MBL 是否通过激活小鼠的 SCN 促进七氟醚麻醉的觉醒。方法：测量MBL（460 nm和800 lux）照射下七氟醚麻醉的诱导和苏醒时间。在七氟醚麻醉期间，在 MBL 下记录皮质脑电图 (EEG) 并计算爆发抑制比 (BSR)。使用或不使用局部电解消融双侧 SCN 的 EEG 和局部场电位 (LFP) 记录进一步探索 SCN 在七氟醚麻醉下 MBL 的唤醒促进作用中的作用。对 c-Fos 进​​行免疫荧光染色以揭示 SCN 激活的可能下游机制。结果：与对诱导时间没有影响不同，MBL 缩短了苏醒时间，脑电图记录显示恢复期间的皮层唤醒。在 2.5% 七氟醚麻醉期间，MBL 导致 BSR 显着降低，脑电图功率在所有频段（纺锤带除外）均显着增加。七氟醚麻醉下的 MBL 暴露增强了 SCN 的神经元活动。这些对 MBL 的反应在 SCN 损伤 (SCNx) 小鼠中被消除。与七氟醚麻醉下的多色白光 (PWL) 相比，MBL 在前额叶皮层 (PFC) 和外侧下丘脑 (LH) 中引起了高水平的 c-Fos 表达，而它对腹外侧视前区的 c-Fos 表达没有影响(VLPO) 和蓝斑基因座 (LC) c-Fos 表达。结论：MBL 通过激活 SCN 及其相关的下游唤醒相关核来促进七氟醚麻醉的行为和脑电图唤醒。这项研究的临床意义值得进一步研究。MBL 通过激活 SCN 及其相关的下游唤醒相关核来促进七氟醚麻醉的行为和脑电图唤醒。这项研究的临床意义值得进一步研究。MBL 通过激活 SCN 及其相关的下游唤醒相关核来促进七氟醚麻醉的行为和脑电图唤醒。这项研究的临床意义值得进一步研究。