Alzheimer anesthesia choroid plexus. glymphatic system magnetic resonance imaging
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摘要

INTRODUCTION: According to the "glymphatic system" hypothesis, brain waste clearance is mediated by a continuous replacement of the interstitial milieu by a bulk flow of cerebrospinal fluid (CSF). Previous reports suggested that this cerebral CSF circulation is only active during general anesthesia or sleep, an effect mediated by the dilatation of the extracellular space. Given the controversies regarding the plausibility of this phenomenon and the limitations of currently available methods to image the glymphatic system, we developed original whole-brain in vivo imaging methods to investigate the effects of general anesthesia on the brain CSF circulation. METHODS: We used magnetic resonance imaging (MRI) and near-infrared fluorescence imaging (NIRF) after injection of a paramagnetic contrast agent or a fluorescent dye in the cisterna magna, in order to investigate the impact of general anesthesia (isoflurane, ketamine or ketamine/xylazine) on the intracranial CSF circulation in mice. RESULTS:In vivo imaging allowed us to image CSF flow in awake and anesthetized mice and confirmed the existence of a brain-wide CSF circulation. Contrary to what was initially thought, we demonstrated that the parenchymal CSF circulation is mainly active during wakefulness and significantly impaired during general anesthesia. This effect was especially significant when high doses of anesthetic agent were used (3% isoflurane). These results were consistent across the different anesthesia regimens and imaging modalities. Moreover, we failed to detect a significant change in the brain extracellular water volume using diffusion weighted imaging in awake and anesthetized mice. CONCLUSION: The parenchymal diffusion of small molecular weight compounds from the CSF is active during wakefulness. General anesthesia has a negative impact on the intracranial CSF circulation, especially when using a high dose of anesthetic agent.

译文

简介: 根据 “glymphatic 系统” 的假设,脑废物清除是通过脑脊液 (CSF) 的大量流动不断替代间质环境介导的。先前的报告表明,这种脑脊髓液循环仅在全身麻醉或睡眠期间活跃,这种作用是由细胞外间隙的扩张介导的。鉴于关于这一现象的合理性的争议和目前可用的成像 glymphatic 系统的方法的局限性, 我们开发了原始的全脑活体成像方法来研究全身麻醉对大脑 CSF 循环的影响。方法: 我们使用磁共振成像 (MRI) 和近红外荧光成像 (NIRF),在大脑池注射顺磁造影剂或荧光染料后, 为了研究全身麻醉 (异氟醚、氯胺酮或氯胺酮/赛拉嗪) 对小鼠颅内 CSF 循环的影响。结果: 体内成像使我们能够成像清醒和麻醉小鼠的脑脊液流动,并确认存在全脑脑脊液循环。与最初的想法相反,我们证明了实质 CSF 循环在清醒期间主要活跃,在全身麻醉期间明显受损。当使用高剂量麻醉剂 (3% 异氟醚) 时,这种效果尤其显著。这些结果在不同的麻醉方案和成像模式中是一致的。此外,我们未能在清醒和麻醉小鼠中使用扩散加权成像检测到脑细胞外水量的显著变化。结论: 在清醒过程中,脑脊液中小分子化合物的实质扩散是活跃的。全身麻醉对颅内脑脊液循环有负面影响,尤其是当使用大剂量麻醉剂时。

General anesthesia

骨科 麻醉 手术操作
概述  :  

麻醉是通过使用药物或其他方法使患者整体或局部暂时失去感觉,以达到无痛的目的进行手术治疗。全麻,顾名思义即全身麻醉,是指通过药物对机体中枢神经系统产生暂时抑制的过程。手术麻醉技术历史久远,发展至今已成为一门重要的学科。 全麻对身体的影响以往有人认为全身麻醉会影响人的智力,这源于1999年《自然》杂志发表的一篇文章,全麻药物对正处于神经系统发育中的年幼动物有明显影响,会导致神经细胞广泛凋亡。但值得注意的是动物不能等同于人类,药物在不同物种内的作用存在差异。其中,神经系统发育的差异,使得

General /ˈdʒenrəl/            

释    义   n.(美、加、俄)杰纳勒尔(人名)

adj. (general) 全体的,普遍的;一般的,普通的;大致的,大概的(方向或地区);首席的

n. (general) 指挥官,军官;大众

同根词   generalized adj.广义的,普遍的;无显著特点的;generally adv.通常;普遍地,一般地;generalization n.概括;普遍化;一般化;generality 概论;普遍性;大部分;generalist(有多方面知识和经验的)通才;多面手

例    句   We not only seek for the general warmth and friendship in our love, but one can share all the secrets with each other.在爱情中寻找的不仅是一般的温情和友谊,而且是一个可以把内心的全部秘密相互托付的人。

 

Anesthesia 英 /,ænɪs'θiːzɪə/ 美 /,ænəs'θiʒə/

释    义   n.(人的)[解剖]跟骨;哺乳动物的空凹足

复数 calcanei

同根词   anesthetic adj.麻醉的;感觉缺失的;anesthetic n.麻醉剂,麻药;anesthetize vt.使麻醉(anaesthetize);使麻痹

例    句   The night music instead of time, everything, I in anesthesia dreams to dance.黑夜的音乐代替了时间,麻醉了一切,我在梦境里翩翩起舞。


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