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.

尽管麻醉剂引起无意识的确切机制仍然未知，但 某些麻醉药激活了调节睡眠并抑制神经系统的神经回路的证据 醒来。尽管全身麻醉和睡眠都激活了一个看似相似（即使不完全相同）的子集 神经元，两个无意识状态之间存在明显的差异，包括唤醒程度 阈值变化和国家过渡的时间尺度。这些相关的神经机制，但 独特的无意识状态知之甚少。 瘫痪区（PZ）最近被确定为非比型眼动（非磁带）睡眠 地区;具体而言，在非REM睡眠期间，PZ（PZ-GABA）中的GABA能神经元活跃。我的初步 数据表明，PZ-GABA在异氟烷暴露期间也很活跃，而PZ-GABA的消融增加也会增加 对异氟烷的抗性。结果还表明，PZ内的非GABA能神经元也涉及 在异氟烷诱导的催眠中。总体问题询问神经电路如何驱动不同状态 通过在PZ-GABA神经元中首次检查，非REM睡眠和异氟烷麻醉会融合和分歧 然后扩展超越PZ，以考虑髓质中的所有细胞类型。假设这些独特的 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 关键状态差异来自独特的细胞激活模式。 我们将在此提案期间要解决的三个关键问题是：1）进行急性可逆激活/抑制作用 PZ促进睡眠神经元改变了麻醉敏感性？ 2）什么是PZ的细胞构成，以及 在每个无意识状态下，哪些细胞被激活？ 3）重叠和不同的元素是什么 在异氟烷暴露期间参与的脑干神经回路与非磁带中参与的脑干电路之间 睡觉？这些问题将通过麻醉和睡眠表型测定，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，侧面 通过活性群体（TRAP）的靶向重组对活性神经元合成的副比较。 拟议的项目将揭示脑干神经电路（包括）的潜在机制 PZ，调节这两个不同的无意识状态。了解大脑如何控制状态 无意识对于临床实践至关重要。它可能会导致更有效，更安全的发质和新的潜力 镇静性催眠麻醉药可能有一天用于睡眠障碍，例如失眠和发肠疾病。