Arousal, orexins and anesthesia

在过去的二十年里，基因研究揭示了调节昼夜节律和睡眠的机制 神经生理学他们还有望揭示麻醉诱导的无意识机制。 对麻醉剂的敏感性在人群中各不相同，有些人需要更高的剂量才能达到 一定的麻醉深度。麻醉抵抗可能存在于人类中，作为麻醉下的意识。 一种形式的超敏反应可能表现为延迟从麻醉中苏醒， 食欲素信号受损的发作性睡眠患者。这项资助的核心假设是， 麻醉剂对调节睡眠和觉醒的内源性神经回路发挥特定的作用。 在麻醉诱导和维持期间，我们假设吸入麻醉剂产生其 通过激活腹侧视前区（VLPO）（中枢睡眠活跃区）的催眠作用 的大脑。从麻醉中苏醒应该依赖于食欲素能（Ox）神经元的重新激活， 大脑中促进和维持清醒的区域。在这项资助的目标1中，我们将绘制神经激活图， 通过c-Fos蛋白免疫组化，最初用于发现唤醒状态的方法相同， 依赖核我们假设c-fos mRNA和蛋白水平在VLPO中被诱导， 在吸入麻醉期间，Ox神经元受到抑制;在正常麻醉期间，这些变化必须逆转。 从麻醉中苏醒在目标2中，我们将评估Ox神经元对诱导的贡献， 使用行为（翻正反射丧失）以及 脑电图（EEC）分析。我们假设，遗传和基因缺陷的小鼠 受损的食欲素信号传导将显示延迟的麻醉苏醒。最后，在目标3中， 证明了给予食欲素激动剂加速了从麻醉中苏醒。我们假设 食欲素激动剂也应该产生c-fos神经元激活模式， 吸入麻醉剂诱导的VLPO激活和Ox神经元抑制。 作为一名接受过神经科学和小鼠遗传学正规培训的麻醉师， 成为学术麻醉师他的最终职业目标是通过以下方式改善围手术期患者护理 更好地理解麻醉剂抑制意识的机制。这项建议会 通过提供睡眠神经生物学（包括脑电图和 EMG采集和分析），药理学研究所需的立体定向手术技术，以及 高级分子生物学他的同事们已经建立了培养年轻教师的记录。一起 以他目前的技能，这些新工具将有助于他成为一个独立的人。 医生科学家之间的桥梁睡眠神经生物学和麻醉作用的接口。

In the past two decades, genetic studies have revealed mechanisms that regulate circadian and sleep neurophysiology. They promise to unveil mechanisms of anesthetic-induced unconsciousness as well. Sensitivity to anesthetics varies across a population with some individuals requiring a higher dose to achieve a given depth of anesthesia. Anesthetic resistance may present in humans as awareness under anesthesia. One form of hypersensitivity may present as delayed emergence from anesthesia and js seen in a subset of narcoleptic patients with impaired orexin signaling. The central hypothesis of this grant is that inhaled anesthetics exert specific effects upon the endogenous neural circuitry regulating sleep and wakefulness. During induction and maintenance of anesthesia, we hypothesize that inhaled anesthetics produce their hypnotic effects through activation of the ventral lateral preoptic area (VLPO), the central sleep-active region of the brain. Emergence from anesthesia should depend upon re-activation of orexinergic (Ox) neurons, a wake-promoting and sustaining region of the brain. In aim 1 of this grant, we will map neural activation through c-Fos protein immunohistochemistry¿the same methodology used initially to find arousal state- dependent nuclei. We hypothesize that c-fos mRNA and protein levels will be induced in VLPO and repressed in Ox neurons during inhaled anesthesia; and that these changes must reverse during normal emergence from anesthesia. In aim 2, we will evaluate the contribution of Ox neurons to induction and emergence from inhaled anesthesia using behavioral (loss of righting reflex) as well as electroencephalographic (EEC) assays. We hypothesize that mice with genetically and pharmacologically impaired orexin signaling will show delayed emergence from anesthesia. Finally, in aim 3, we will demonstrate that administration of orexin agonists speeds emergence from anesthesia. We hypothesize that orexin agonists should also produce c-fos neuronal activation patterns that attenuate (or reverse) both inhaled anesthetic-induced activation of VLPO and inhibition of Ox neurons. As an anesthesiologist formally trained in neuroscience and mouse genetics, Dr. Kelz is firmly committed to a career in academic anesthesia. His ultimate career goal is to improve perioperative patient care through a better understanding of the mechanisms by which anesthetics suppress consciousness. This proposal will enhance his training toward that end by providing formal education in sleep neurobiology (including EEG and EMG acquisition and analysis), stereotactic surgerical techniques necessary for pharmacologic studies, and advanced molecular biology. His co-mentors have established records of nuturing junior faculty. Together with his current skill set, these new tools will help transition him towards becoming an independent physician-scientist by bridging the interface between sleep neurobiology and anesthetic action.