The electrophysiological studies in the action of xenon on the central nervous system

本文比较了氙（Xe）和一氧化二氮（N_2O）对中枢神经系统电活动的影响。本文记录了猫的脑电图（EEG）、中脑网状结构多单位活动（R-MUA）和体感诱发电位（SEP）。使用2%和5%七氟烷进行基础麻醉。使用2%七氟烷时，70%的七氟烷最初产生节律性慢波，随后在EEG上出现高振幅尖波，被低振幅慢波打断。N20 70%降低了EEG活动的幅度，这与R-MUA的增加有关。MUA. N2 O对SEP的正向和负向振幅的抑制作用均大于N2 O。两种麻醉药都能增加EEG上的棘波频率，并促进R-MUA。我们还通过抑制皮肤伤害性刺激诱发的脊髓宽动态范围神经元反应来评估两种麻醉药的效力。捏）刺激，以猫麻醉chlorarose和氨基甲酸乙酯。在70%的浓度下，11个神经元中有7个对捏刺激的反应受到抑制。N_2O对11个神经元中的8个有抑制作用，抑制率为70%。在被两种麻醉剂抑制的六个神经元中比较了N2 O和N2 O的效力。吸入N_2O 20 min后，捏压反应抑制率为49.5%，而氧气中70%的N_2O抑制率为45.9%。N_2O和CO_2浓度间差异不显著。这些结果表明，N2 O对脑背景活动有刺激作用，对脑反应能力有抑制作用，其作用强于N2 O; N2 O和N2 O对脊髓背角神经元的抑制程度相似。

We have compared the effects of xenon (Xe) and nitrous oxide (N2O) on central nervous system electrical activity. We recorded the electroencephalogram (EEG), multi-unit activity of midbrain reticular formation (R-MUA) and somatosensory evoked potentials (SEP) in cats. Basal anesthesia with 2% and 5% sevoflurane was used. With 2% sevoflurane, 70% Xe initially produced rhythmic slow waves that were followed by bursts of high-amplitude sharp waves interrupted by low amplitude slow waves on the EEG.Xe induced an initial increase, followed by a decrease in R-MUA.N20 70% decreased the amplitude of EEG activity that was associated with an increase in R-MUA.Xe suppressed the amplitude of both the initial positive and negative deflections of the SEP to a greater extent than N2O.With 5% sevoflurane anesthesia, both anesthetics increased the frequency of spikes on the EEG and facilitated R-MUA.We also assessed the potency of both anesthetics by the inhibition of the responses of wide dynamic range neuron in the spinal cord evoked by cutaneous noxious (pinch) stimulation to a hindpow in cats anesthetized with chrolarose and urethane. During 70% Xe inhalation, the responses of 7 of 11 neurons to pinch stimulation were suppressed. N2O,70%, suppressed it in 8 of 11 neurons. The potency of Xe and N2O was compared in six neurons that were suppressed by both anesthetics. After 20min of Xe inhalation, the response to pinch was suppressed to 49.5%, while N2O,70% in oxygen, suppressed it to 45.9%. The difference between N2O and Xe was not significant. These findings indicate that Xe has a stimulatory action on brain background activity and a suppressive action on brain reactive capability that is more potent than that of N2O ; Xe and N2O suppresses the spinal dorsal horn neurons to a similar degree.