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。他们承诺还将揭示麻醉剂诱导的无意识的机制。 不同人群对麻醉剂的敏感性不同，有些人需要更高的剂量才能达到 给定的麻醉深度。麻醉抵抗可能在人类中表现为麻醉下的觉醒。 一种形式的超敏反应可能表现为麻醉后延迟苏醒和js，见于 食欲素信号受损的发作性睡病患者。这项资助的中心假设是吸入 麻醉药对调节睡眠和清醒的内源性神经回路产生特定的影响。 在麻醉诱导和维持期间，我们假设吸入麻醉剂产生 激活中央睡眠活动区腹侧视前区(VLPO)的催眠效应 大脑的一部分。从麻醉中苏醒应该取决于食欲素能(Ox)神经元的重新激活 大脑中促进和维持觉醒的区域。在这笔赠款的目标1中，我们将映射神经激活 通过c-Fos蛋白免疫组织化学，最初用于发现觉醒状态的相同方法- 从属核。我们假设c-fos的mRNA和蛋白水平将在VLPO和VLPO中被诱导 吸入麻醉期间Ox神经元的抑制；在正常情况下，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神经元在诱导和 使用行为(翻正反射丧失)的吸入性麻醉苏醒 脑电(EEC)分析。我们假设，从遗传学和药理学上讲， 食欲素信号受损将显示麻醉后延迟苏醒。最后，在目标3中，我们将 证明服用增食欲素激动剂可以加快麻醉苏醒的速度。我们假设 食欲素激动剂也应该产生c-fos神经元激活模式，从而减弱(或逆转)两者 吸入麻醉剂对VLPO的激活和对Ox神经元的抑制。 作为一名训练有素的神经科学和老鼠遗传学的麻醉师，凯尔茨博士坚定地致力于 在学术麻醉方面的职业生涯。他的最终职业目标是通过以下方式改善围手术期病人的护理 更好地理解麻醉剂抑制意识的机制。这项提议将 通过提供睡眠神经生物学的正式教育(包括脑电波和 肌电采集和分析)，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。他的合作导师已经建立了培养初级教员的记录。同舟共济 以他目前的技能，这些新工具将帮助他向独立的方向过渡 在睡眠神经生物学和麻醉作用之间架起桥梁的内科医生和科学家。

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.