Arousal, orexins and anesthesia

描述（由申请人提供）：在过去的二十年中，遗传研究揭示了调节昼夜节律和睡眠神经生理学的机制。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给定的麻醉深度。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，并且见于食欲素信号受损的发作性睡眠患者亚组。这项资助的中心假设是吸入麻醉剂对调节睡眠和觉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通过激活腹侧视前区（VLPO）（大脑的中枢睡眠活跃区）产生催眠作用。从麻醉中苏醒应该取决于食欲素能（Ox）神经元的重新激活，这是大脑的一个促进和维持清醒的区域。在这项资助的目标1中，我们将通过c-Fos蛋白免疫组织化学绘制神经激活图？与最初用于寻找唤醒状态依赖核团的方法相同。我们推测，c-fos mRNA和蛋白水平将诱导VLPO和抑制在牛神经元吸入麻醉过程中，这些变化必须扭转在正常的出现从麻醉。在目标2中，我们将使用行为（翻正反射丧失）以及脑电图（EEC）测定来评估Ox神经元对吸入麻醉诱导和苏醒的贡献。我们假设，基因和食欲素信号受损的小鼠将表现出延迟从麻醉中苏醒。最后，在目标3中，我们将证明给予食欲素激动剂可加速麻醉苏醒。我们假设，食欲素激动剂也应该产生c-fos神经元激活模式，减弱（或逆转）吸入麻醉剂诱导的VLPO激活和抑制Ox神经元。作为一名接受过神经科学和小鼠遗传学正式培训的麻醉师，Kelz博士坚定地致力于学术麻醉的职业生涯。他的最终职业目标是通过更好地理解麻醉剂抑制意识的机制来改善围手术期患者的护理。这项建议将通过提供睡眠神经生物学（包括EEG和EMG采集和分析）、药理学研究所需的立体定向手术技术和高级分子生物学方面的正规教育，加强他为此目的所做的培训。他的同事们已经建立了培养年轻教师的记录。再加上他目前的技能，这些新工具将帮助他过渡到成为一个独立的医生，科学家之间的桥梁睡眠神经生物学和麻醉作用的接口。

DESCRIPTION (provided by applicant): 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.