Anesthesia and Sleep: Mechanisms of Generating Two Similar Yet Distinct Unconscious States in the Medulla

麻醉和睡眠：髓质中产生两种相似但不同的无意识状态的机制

• 批准号: 10711854
• 负责人: Toshihiro Imamura
• 金额: $ 40.63万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2028-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10711854
• 关键词: Ablation; Acute; Address; Anesthesia procedures; Anesthetics; Arousal; Automobile Driving; Biological Assay; Brain; Brain Stem; Cells; Coma; Data; Elements; General Anesthesia; Genetic Recombination; Hypnosis; In Situ Hybridization; Isoflurane; Mediating; Narcolepsy; Neural Inhibition; Neurons; Pattern; Persons; Pharmaceutical Preparations; Phenotype; Population; Procedures; Public Health; Resistance; Sedation procedure; Side; Sleep; Sleep Disorders; Sleeplessness; System; Techniques; Unconscious State; Wakefulness; cell type; clinical care; clinical practice; gamma-Aminobutyric Acid; hypnotic; mind control; neural circuit; neuromechanism; non rapid eye movement; sedative; single nucleus RNA-sequencing; sleep regulation; transcriptomics

Although the exact mechanisms by which anesthetics induce unconsciousness remain unknown, there is evidence that some anesthetics activate neural circuits regulating sleep and inhibit neural systems promoting waking. Despite general anesthesia and sleep both activating a subset of seemingly similar, if not identical, neurons, there are clear differences between the two unconscious states, including the degree of arousal threshold changes and the timescale of state transition. The neural mechanisms underlying these related, yet distinct unconscious states are poorly understood. The parafacial zone (PZ) has recently been identified as a non-rapid-eye-movement (non-REM) sleep-promoting region; specifically, GABAergic neurons in the PZ (PZ-GABA) are active during non-REM sleep. My preliminary data demonstrate that PZ-GABA are also active during isoflurane exposure, and ablation of PZ-GABA increases resistance to isoflurane. The results also suggest that non-GABAergic neurons within the PZ are also involved in isoflurane-induced hypnosis. The overarching question asks how the neural circuitry driving distinct states of non-REM sleep and isoflurane anesthesia converge and diverge by first examining in PZ-GABA neurons, and then expanding beyond the PZ to consider all cell types in the medulla. It is hypothesized that these distinct endogenous and drug-induced unconscious states are generated by partially overlapping shared circuits but that key state differences arise from distinctive cellular activation patterns. The three key questions we will address during this proposal are: 1) Does acute reversible activation/inhibition of the PZ sleep-promoting neurons alter anesthetic sensitivity? 2) What is the cellular makeup of the PZ, and which cells are activated during each unconscious state? and 3) What are the overlapping and different elements between the brainstem neural circuits engaged during isoflurane exposure and those engaged during non-REM sleep? These questions will be addressed by anesthetic and sleep phenotyping assays, the single-cell level transcriptomic analysis by single nucleus RNA sequencing followed by multiplex in situ hybridization, and side- by-side comparison of ensembles of active neurons by Targeted Recombination in Active Population (TRAP). The proposed projects will uncover the underlying mechanism of how the brainstem neural circuits, including PZ, mediate these two different unconscious states. Understanding how the brain controls states of unconsciousness is vital for clinical practice. It can lead to more effective and safer somnogens and new potential sedative hypnotic anesthetics that may one day be used for sleep disorders such as insomnia and narcolepsy.

尽管麻醉剂引起意识丧失的确切机制仍不清楚，但 有证据表明，某些麻醉剂会激活调节睡眠的神经回路并抑制促进睡眠的神经系统 醒来。尽管全身麻醉和睡眠都会激活看似相似（即使不相同）的子集， 神经元，两种无意识状态之间存在明显差异，包括唤醒程度 阈值变化和状态转换的时间尺度。这些相关的神经机制 人们对不同的无意识状态知之甚少。 面旁区 (PZ) 最近被确定为非快速眼动 (non-REM) 促进睡眠的区域 地区;具体来说，PZ 中的 GABA 能神经元 (PZ-GABA) 在非快速眼动睡眠期间处于活跃状态。我的初步 数据表明，PZ-GABA 在异氟烷暴露期间也很活跃，并且 PZ-GABA 的消融增加 对异氟烷有抵抗力。结果还表明 PZ 内的非 GABA 能神经元也参与其中 在异氟烷诱导的催眠中。最重要的问题是神经回路如何驱动不同的状态 通过首先检查 PZ-GABA 神经元，非快速眼动睡眠和异氟烷麻醉的收敛和发散，以及 然后扩展到 PZ 之外以考虑髓质中的所有细胞类型。据推测，这些不同的 内源性和药物引起的无意识状态是由部分重叠的共享电路产生的，但 关键状态差异源于独特的细胞激活模式。 我们在此提案中将解决的三个关键问题是：1）急性可逆激活/抑制是否会发生？ PZ 促进睡眠的神经元会改变麻醉敏感性吗？ 2) PZ 的细胞组成是什么，以及 在每个无意识状态下哪些细胞被激活？ 3）有哪些重叠和不同的元素 异氟烷暴露期间参与的脑干神经回路与非快速眼动睡眠期间参与的脑干神经回路之间的关系 睡觉？这些问题将通过麻醉和睡眠表型分析、单细胞水平来解决 通过单核 RNA 测序进行转录组分析，然后进行多重原位杂交和侧位杂交 通过活动群体中的靶向重组（TRAP）对活动神经元集合进行旁路比较。 拟议的项目将揭示脑干神经回路的潜在机制，包括 PZ，调解这两种不同的无意识状态。了解大脑如何控制状态 无意识对于临床实践至关重要。它可以带来更有效、更安全的催眠剂和新的潜力 镇静催眠麻醉剂，有一天可能用于治疗失眠和嗜睡症等睡眠障碍。