Volatile Anesthetics and Metabolism

项目摘要 现代医学的一个真正的谜团已经持续了150多年；其机制(S) 挥发性麻醉剂(VAS)导致可逆性意识丧失仍是一个未解之谜。vbl.使用 遗传学方法，我们证明了线粒体复合体I，线粒体的一个入口点 电子传输链，专门控制多种物种的敏感性，包括蠕虫和 人类，转到VAS。这些广泛的系统发育效应表明，一种古老的机制就在手边，它将 线粒体在VAS存在时对突触沉默的作用。 我们通过利用Ndufs4(KO)，一种复合体I缺陷的小鼠，开始了对小鼠的机制研究 功能正常，对VAS高度敏感。检测细胞特异性Ndufs4(KO)小鼠，我们发现VA 敏感性完全由谷氨酸能KO控制，不受GABA能或 胆碱能神经元。令人惊讶的是，NDUFS4的星形细胞特异性KO只有在从 VAS。初步数据表明，蓝斑中的神经元介导了这一效应。这个新奇的角色 星形胶质细胞为研究关键的唤醒途径提供了一种新的方法。此外，我们正在探索 麻醉诱导神经毒性(AIN)的潜在机制。从我们对线虫的研究中，我们得到了 确定了新的候选分子，可以在小鼠身上测试为AIN疗法。我们证明了抑制作用 内质网中未折叠的蛋白质反应，或抑制mTOR，一种细胞代谢 切换，缓解了蠕虫体内的AIN。我们正在探索这些通路在AIN中的作用，并将它们与 令人振奋的新数据表明，维生素A本身会产生新生小鼠特有的代谢变化。 许多问题仍未得到解答。1.复合I缺陷是如何控制VA敏感性的。我们 结果表明，Ndufs4(KO)的兴奋性神经传递对异氟醚的抑制敏感 与WT相比。我们最近的数据表明，异氟醚抑制WT和KO的突触内吞作用 这种抑制是由于三磷酸腺苷产生减少所致。我们的目标是描述 VAS抑制神经递质内吞作用的机制。2.转导途径是什么？ 新生小鼠的AIN；如何抑制这些途径？我们正在将线虫的研究扩展到 测试令人兴奋的新的小分子候选分子，可能会减轻小鼠的AIN。我们还在探索内质网应激 MTOR活性是介导小鼠AIN的潜在信号通路。3.线粒体是如何 星形胶质细胞在麻醉状态下控制觉醒的功能？我们正在研究星形细胞 确定星形胶质细胞在VA暴露期间和之后如何影响突触功能的信号。 从麻醉状态苏醒所必需的星形胶质细胞/神经通路将是 调查过了。线粒体功能与蠕虫、小鼠和人类在VAS中的行为有关。我们的建议 研究的目的是确定VAS的基本分子作用机制。

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.