Volatile Anesthetics and Metabolism

挥发性麻醉剂和代谢

• 批准号: 10352378
• 负责人: PHILIP G MORGAN
• 金额: $ 82万
• 依托单位: SEATTLE CHILDREN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-03-01 至 2026-02-28
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10352378
• 关键词: Affect; Anesthetics; Animals; Arousal; Astrocytes; Behavior; Caenorhabditis elegans; Cells; Complex; Conscious; Data; Defect; Electron Transport; Endocytosis; Endoplasmic Reticulum; FRAP1 gene; Glutamates; Goals; Hand; Human; Hypersensitivity; Isoflurane; Knockout Mice; Laboratories; Link; Long-Term Effects; Mediating; Metabolic; Metabolism; Mitochondria; Modern Medicine; Molecular Mechanisms of Action; Mus; Nematoda; Neural Pathways; Neurons; Neurotransmitters; Pathway interactions; Phylogenetic Analysis; Production; Proteins; Role; Signal Pathway; Signal Transduction; Synapses; Testing; Unconscious State; Work; cholinergic neuron; clinical care; endoplasmic reticulum stress; genetic approach; locus ceruleus structure; mTOR inhibition; man; neonatal mice; neurotoxicity; neurotransmission; novel; novel strategies; response; small molecule; synaptic function

Project Summary A true enigma of modern medicine has persisted for over 150 years; the mechanism(s) by which volatile anesthetics (VAs) produce reversible loss of consciousness remains an unsolved mystery. Using genetic approaches, we demonstrated that mitochondrial complex I, an entry point of the mitochondrial electron transport chain, specifically controls the sensitivity of multiple species, including worms and humans, to VAs. These broad phylogenetic effects indicate that an ancient mechanism is at hand, linking mitochondrial function to synaptic silencing in the presence of VAs. We began mechanistic studies in mice by exploiting Ndufs4(KO), a mouse defective in complex I function and extremely hypersensitive to VAs. Testing cell-specific Ndufs4(KO) mice, we found that VA sensitivity was fully controlled by glutamatergic KO, with no effect of loss of NDUFS4 from GABAergic or cholinergic neurons. Surprisingly, an astrocytic-specific KO of NDUFS4 was defective only in arousal from VAs. Preliminary data indicate that neurons in the locus coeruleus mediate this effect. This novel role of astrocytes offers a new approach to investigate crucial arousal pathways. In addition, we are exploring the mechanisms underlying anesthetic induced neurotoxicity (AIN). From our work in nematodes, we have identified new candidate molecules that can be tested as AIN therapies in mice. We showed that inhibition of the unfolded protein response in the endoplasmic reticulum, or inhibition of mTOR, a cellular metabolic switch, alleviated AIN in worms. We are exploring the roles of these pathways in AIN, and relating them to exciting new data which indicate that VAs themselves produce metabolic changes specific to neonatal mice. Many questions remain unanswered. 1. How do complex I defects control VA sensitivity. We showed that excitatory neurotransmission in Ndufs4(KO) was hypersensitive to isoflurane inhibition compared to WT. Our recent data suggest that isoflurane inhibits synaptic endocytosis in both WT and KO animals and that this inhibition results from a decrease in ATP production. Our aims are to characterize the mechanism underlying inhibition of neurotransmitter endocytosis by VAs. 2. What pathways transduce AIN in neonatal mice; how can those pathways be inhibited? We are extending C. elegans studies to test exciting new small molecule candidates that may alleviate AIN in mice. We are also exploring ER-stress and mTOR activity as potential signaling pathways mediating AIN in mice. 3. How does mitochondrial function in astrocytes control arousal from the anesthetized state? We are studying astrocyte signaling to determine how astrocytes affect synaptic function during and following VA exposure. Astrocyte/neural pathways necessary for emergence from the anesthetized state will be investigated. Mitochondrial function is linked to behavior in VAs in worms, mice, and man. Our proposed studies are aimed to identify the basic, molecular mechanisms of action of VAs.

项目摘要 现代医学的一个真正的谜团已经持续了150多年; 挥发性麻醉剂（VA）产生可逆的意识丧失仍然是一个未解之谜。使用 通过遗传学方法，我们证明了线粒体复合物I，线粒体的入口点， 电子传递链，具体控制多个物种的敏感性，包括蠕虫和 从人类到退伍军人这些广泛的系统发育效应表明，一个古老的机制就在眼前， 线粒体功能对VA存在时突触沉默的影响。 我们通过利用Ndufs 4（KO），一种在复合物I中有缺陷的小鼠， 对VA极度敏感。测试细胞特异性Ndufs 4（KO）小鼠，我们发现VA 敏感性完全由GABA能KO控制，而GABA能或GABA能KO对NDUFS 4的损失没有影响。 胆碱能神经元令人惊讶的是，星形胶质细胞特异性的NDUFS 4 KO仅在从神经元的唤醒中有缺陷。 退伍军人协会初步数据表明，蓝斑神经元介导这种效应。这个新角色 星形胶质细胞提供了一种新的方法来研究关键的唤醒途径。此外，我们正研究 麻醉剂诱导的神经毒性（AIN）的潜在机制。从我们对线虫的研究中， 确定了新的候选分子，可以在小鼠中作为AIN疗法进行测试。我们发现抑制 内质网中未折叠蛋白质反应的抑制，或mTOR的抑制， 交换机，减轻了蠕虫中的AIN。我们正在探索这些途径在AIN中的作用，并将其与 令人兴奋的新数据表明VA本身产生新生小鼠特有的代谢变化。 许多问题仍然没有答案。1.复杂I型缺陷如何控制VA敏感性。我们 结果显示，Ndufs 4（KO）的兴奋性神经传递对异氟醚抑制高度敏感 与WT相比。我们最近的数据表明，异氟烷抑制WT和KO的突触内吞作用 这种抑制作用是由ATP产生减少引起的。我们的目标是描述 VA抑制神经递质内吞的潜在机制。2.什么途径？ 新生小鼠中的AIN;如何抑制这些途径？我们扩展C。elegans研究 测试令人兴奋的新的小分子候选物，可以减轻小鼠的AIN。我们也在探索ER压力 和mTOR活性作为介导小鼠AIN的潜在信号通路。3.线粒体是如何 星形胶质细胞的功能控制从麻醉状态唤醒？我们在研究星形胶质细胞 信号传导以确定星形胶质细胞如何在VA暴露期间和之后影响突触功能。 从麻醉状态中出现所需的星形胶质细胞/神经通路将被破坏。 研究了线粒体功能与蠕虫、小鼠和人类VA的行为有关。 研究的目的是确定VA作用的基本分子机制。