DataSheet1_Parabrachial nucleus astrocytes regulate wakefulness and isoflurane anesthesia in mice.docx

Background: The parabrachial nucleus (PBN) is an important structure regulating the sleep–wake behavior and general anesthesia. Astrocytes in the central nervous system modulate neuronal activity and consequential behavior. However, the specific role of the parabrachial nucleus astrocytes in regulating the sleep-wake behavior and general anesthesia remains unclear.
Methods: We used chemogenetic approach to activate or inhibit the activity of PBN astrocytes by injecting AAV-GFAabc1d-hM3Dq-eGFP or AAV-GFAabc1d-hM4Di-eGFP into the PBN. We investigated the effects of intraperitoneal injection of CNO or vehicle on the amount of wakefulness, NREM sleep and REM sleep in sleep–wake behavior, and on the time of loss of righting reflex, time of recovery of righting reflex, sensitivity to isoflurane, electroencephalogram (EEG) power spectrum and burst suppression ratio (BSR) in isoflurane anesthesia.
Results: The activation of PBN astrocytes increased wakefulness amount for 4 h, while the inhibition of PBN astrocytes decreased total amount of wakefulness during the 3-hour post-injection period. Chemogenetic activation of PBN astrocytes decreased isoflurane sensitivity and shortened the emergence time from isoflurane-induced general anesthesia. Cortical EEG recordings revealed that PBN astrocyte activation decreased the EEG delta power and BSR during isoflurane anesthesia. Chemogenetic Inhibition of PBN astrocytes increased the EEG delta power and BSR during isoflurane anesthesia.
Conclusion: PBN astrocytes are a key neural substrate regulating wakefulness and emergence from isoflurane anesthesia.

背景：臂旁核（parabrachial nucleus, PBN）是调控睡眠-觉醒行为与全身麻醉的关键核团。中枢神经系统（central nervous system）内的星形胶质细胞（astrocytes）可调节神经元活动及后续行为。然而，臂旁核星形胶质细胞在调控睡眠-觉醒行为与全身麻醉中的具体作用仍未明确。
方法：本研究采用化学遗传学（chemogenetic）方法，通过向臂旁核注射AAV-GFAabc1d-hM3Dq-eGFP或AAV-GFAabc1d-hM4Di-eGFP，以激活或抑制臂旁核星形胶质细胞的活性。我们检测了腹腔注射CNO或溶剂后，睡眠-觉醒行为中觉醒时长、非快速眼动睡眠（Non-rapid eye movement sleep, NREM sleep）与快速眼动睡眠（Rapid eye movement sleep, REM sleep）的总量，以及异氟烷（isoflurane）麻醉状态下的翻正反射消失时间、翻正反射恢复时间、异氟烷敏感性、脑电图（electroencephalogram, EEG）功率谱与爆发抑制比（burst suppression ratio, BSR）的变化。
结果：激活臂旁核星形胶质细胞可使觉醒时长增加4小时，而抑制臂旁核星形胶质细胞则会在注射后3小时内降低总觉醒时长。化学遗传学激活臂旁核星形胶质细胞可降低异氟烷敏感性，并缩短异氟烷诱导的全身麻醉后的苏醒时间。皮层脑电图记录显示，臂旁核星形胶质细胞激活可降低异氟烷麻醉期间的脑电图δ波功率与爆发抑制比。化学遗传学抑制臂旁核星形胶质细胞则可升高异氟烷麻醉期间的脑电图δ波功率与爆发抑制比。
结论：臂旁核星形胶质细胞是调控觉醒与异氟烷麻醉后苏醒的关键神经底物。