Turle N, Saget A, Zouani B, Risso J J
Department of Neurochemistry, I. M. N. S. S. A., Toulon Naval, France.
Neurochem Res. 1998 Jul;23(7):997-1003. doi: 10.1023/a:1021040607207.
Inert gas narcosis is a neurological syndrome inducing several psychomotor disorders. Nitrogen narcosis represents the major cause of performances decrease concerning divers, in the depth range of 30 to 90 meters (0.3 to 0.9 MegaPascal). As narcosis affects motor functions, we chose to study the nigro-striatal dopaminergic pathway owing to its involvement in psychomotor disorders. The aim of this study is to compare, in the Sprague-Dawley rats striatium, changes in extracellular concentrations of Dopamine and its metabolites: Dihydroxyphenylacetic Acid (DOPAC) and Homovanillic Acid (HVA) under a normobaric narcosis (20; 40, and 60% of Nitrous Oxide (N2O)) on one hand, and under 0.9 MegaPascal of Nitrox (Nitrogen Oxygen normoxic mixture) on the other hand. In fact, if these two conditions are similar, normobaric narcosis would allow us to explain nitrogen narcosis mechanisms without any pressure effect. The first emergence of Dopamine and metabolites variations occurs around 40% of N2O. Dopamine decreases by 45% and is accompanied by a DOPAC diminution of 7% while HVA concentrations remain constant. Under 60% N2O, these decrease have a greater amplitude. The Dopamine variations obtained under 0.9 Mpa of Nitrox are closed to alterations induced by 60% of N2O (DA decreases by 70%).
惰性气体麻醉是一种引发多种精神运动障碍的神经综合征。氮麻醉是潜水员在30至90米（0.3至0.9兆帕斯卡）深度范围内表现下降的主要原因。由于麻醉会影响运动功能，我们选择研究黑质纹状体多巴胺能通路，因为它与精神运动障碍有关。本研究的目的是比较在常压麻醉（20%、40%和60%氧化亚氮（N₂O））以及0.9兆帕斯卡的氮氧混合气（氮氧常氧混合气）条件下，Sprague-Dawley大鼠纹状体内多巴胺及其代谢产物：二羟基苯乙酸（DOPAC）和高香草酸（HVA）细胞外浓度的变化。事实上，如果这两种情况相似，常压麻醉将使我们能够在不考虑任何压力影响的情况下解释氮麻醉的机制。多巴胺及其代谢产物变化首次出现约在40%的N₂O浓度时。多巴胺减少45%，同时DOPAC减少7%，而HVA浓度保持不变。在60%的N₂O浓度下，这些减少幅度更大。在0.9兆帕斯卡的氮氧混合气条件下获得的多巴胺变化与60%的N₂O诱导的变化相近（多巴胺减少70%）。
