静脉麻醉药致意识消失作用与睡眠-觉醒通路的相关性研究

Loss of consciousness is the most essential feature of general anesthesia, research on loss of consciousness induced by anesthetics is crucial for revealing the mechanism of general anesthesia. Previous studies have found that unconsciousness induced by intravenous anesthetic propofol is similar to natural sleep, suggesting that the activation of sleep pathways may be involved in the action of propofol, however the underlying mechanisms still elusive. Additionally, whether sleep-arouse pathways linked to the unconsciousness induced by clinical anesthetics with different pharmacological properties is not known. In this project, based on our previous work, we will focus on the ventrolateral preoptic area (VLPO), tuberomammillary nucleus (TMN) and locus coeruleus (LC) in the sleep-arouse pathways, to investigate the effects of three intravenous anesthetics (propofol, etomidate and dexmedetomidine) on the functional neural connection, neuronal activities and neurotransmitter release in the sleep-arouse pathways in rat using electroencephalogram , brain microdialysis and electrophysiology. In addition, by specifically regulate neurons in vivo, we will study the effects of intravenous anesthetics on the neural circuits and synaptic transmission in these sleep-arouse associated nuclei using DREADD (designer receptors exclusively activated by a designer drug) technique and zebrafish model. This project will provide reliable data to prove whether the sleep-arouse pathways were involved in the mechanism of loss of consciousness induced by general anesthetics.

意识消失是全身麻醉最基本的特征，而揭示全麻致意识消失机制是全麻药作用研究的关键。前期工作发现静脉麻醉药异丙酚致意识消失与自然睡眠之间存在相似性，提示异丙酚的全麻作用可能涉及睡眠通路的激活，但相关机制尚未阐明。此外，临床常用不同种类的全麻药，致意识消失作用是否均涉及睡眠相关通路也罕见报道。因此，本项目基于前期研究基础，以睡眠-觉醒调控通路为切入点，针对该通路的三组关键神经核团：下丘脑腹外侧视前区、结节乳状体及蓝斑，通过脑电图、微透析与电生理技术，探索静脉麻醉药异丙酚、依托咪酯及右美托咪定对活体大鼠睡眠-觉醒脑区功能连接、核团电活动和神经递质的影响，以明确三种药物影响睡眠-觉醒通路的异同；同时运用药物遗传学技术和斑马鱼模式动物，通过特异性的调控活体神经元，在神经网络与突触水平阐明全麻药致意识消失的作用机制。本项目旨在为探索静脉麻醉药致意识消失的机制提供靶向性作用的实验与理论依据。

项目背景：意识消失是全身麻醉最基本的特征，而揭示全麻致意识消失机制是全麻药作用研究的关键。前期工作发现静脉麻醉药异丙酚致意识消失与自然睡眠之间存在相似性，提示异丙酚的全麻作用可能涉及睡眠通路的激活，但相关机制尚未阐明。.主要研究内容：以睡眠--觉醒系统关键核团脑电活动和关键神经递质代谢变化作为观察指标，研究分析异丙酚对睡眠--觉醒系统关键核团功能影响的差异，并结合光遗传学、脑片膜片钳电生理、不同动物模型（鼠和斑马鱼）等探讨丙泊酚致意识消失的机制。.重要结果：1. 发现异丙酚对VLPO神经元突触后电流的抑制作用是由组胺能H1和H2受体介导的；2. 臂旁核在丙泊酚致意识消失的早期阶段并未被抑制，但在苏醒期可能发挥重要作用；3. 蓝斑内去甲肾上腺素系统在静脉全麻诱导和合并中起调节作用。.关键数据：1. 斑马鱼蓝斑神经元毁损组与对照组分别为63.9±0.9和65.6±1.0cm，但在丙泊酚诱导下（对照组为176.5±6.0s，消融组为148.3±7.0s）或依托咪酯诱导（对照组160.8±6.4s，消融组115.4±6.4s）麻醉比对照组用时更短。2。局部注射异丙酚或依托咪酯完全抑制大鼠蓝斑神经元的自发放电（异丙酚前后：1.8±0.3 vs 0.05±0.03 Hz；依托咪酯前后：2.5±0.4 vs 0.03±0.03 Hz）并导致蓝斑神经元超极化（异丙酚用药前后：-55.1±1.2和-63.8±2.1 mV；依托咪酯用药前后：-59.0±1.5和-61.8±1.9 mV）。3. 局部微注射异丙酚或依托咪酯可大幅度减少EPSCs（异丙酚前后对比：17.1±3.1 vs 2.1±1.0hz；依托咪酯前后对比：18.0±2.3 vs 4.6±0.8hz） .科学意义：探明全身麻醉与自然睡眠之间的异同，从全麻药物对睡眠-觉醒系统的作用中发现全身麻醉致意识消失机制的线索。