Faculté de Médecine, Université de la Méditerranée, UMR MD2P2COE Boulevard Pierre Dramard, Marseille 13916, Cedex 20, France.
Exp Physiol. 2010 Jan;95(1):153-9. doi: 10.1113/expphysiol.2009.049460. Epub 2009 Aug 14.
Based on previous observations in hyperbaric hyperoxia, we hypothesized that normobaric hyperoxia, often used during general anaesthesia and resuscitation, might also induce a neuromuscular excitability. In healthy volunteers, we studied the consequences of a 50 min period of pure oxygen breathing on the neuromuscular conduction time (CT), the amplitude of the compound evoked muscle potential (M-wave), the latency and amplitude of the Hoffman reflex (H reflex) and the electromyographic tonic vibratory response (TVR) of the flexor digitorum superficialis muscle to explore the proprioceptive reflex loop. Hyperoxia-induced oxidative stress was measured by the changes in blood markers of lipid peroxidation (thiobarbituric acid reactive substances, TBARS) and antioxidant response (reduced ascorbic acid, RAA). During hyperoxia, the M-wave amplitude increased, both CT and H reflex latency were shortened, and the H reflex amplitude increased. By contrast, TVR significantly decreased. Concomitantly, an oxidative stress was assessed by increased TBARS and decreased RAA levels. This study shows the existence of dual effects of hyperoxia, which facilitates the muscle membrane excitability, nerve conduction and spinal reflexes, but reduces the gain of the proprioceptive reflex loop. The activation of the group IV muscle afferents by hyperoxia and the resulting oxidative stress might explain the TVR depression.
基于以往高压氧环境下的观察结果，我们假设常氧环境下（常氧环境常用于全身麻醉和复苏）也可能诱导神经肌肉兴奋性。我们在健康志愿者中研究了纯氧呼吸 50 分钟对神经肌肉传导时间（CT）、复合诱发肌肉电位（M 波）幅度、霍夫曼反射（H 反射）潜伏期和幅度以及屈指浅肌的肌电图紧张性振动反应（TVR）的影响，以探讨本体感受反射环路。通过血液脂质过氧化（硫代巴比妥酸反应物质，TBARS）和抗氧化反应（还原型抗坏血酸，RAA）标志物的变化来测量氧诱导的氧化应激。在高氧环境下，M 波幅度增加，CT 和 H 反射潜伏期缩短，H 反射幅度增加。相比之下，TVR 显著降低。同时，通过增加 TBARS 和降低 RAA 水平评估氧化应激。这项研究表明，高氧存在双重作用，既促进了肌肉膜的兴奋性、神经传导和脊髓反射，但降低了本体感受反射环路的增益。高氧对 IV 组肌传入纤维的激活以及由此产生的氧化应激可能解释了 TVR 的抑制。
