Alterations in spinal, but not cerebral, cerebrospinal fluid Na+ concentrations affect the isoflurane minimum alveolar concentration in rats
Alterations in spinal, but not cerebral, cerebrospinal fluid Na+ concentrations affect the isoflurane minimum alveolar concentration in rats
复制标题
DOI：
10.1213/01.ane.0000278090.88402.26
复制
发表时间：
2007-09-01
影响因子：
5.7
通讯作者：
Sonner, James M.
中科院分区：
文献类型：
--
作者：
Laster, Michael J.;Zhang, Yi;Sonner, James M.
背景技术背景：先前的研究表明，氟烷的MAC（吸入麻醉剂的最小肺泡浓度，使50%暴露于伤害性刺激的受试者不动）与中枢神经系统Na+浓度直接相关。然而，这些研究总体上改变了Na+浓度，因此没有区分对脊髓的影响和对大脑的影响。这是一个重要的区别，因为脊髓似乎是介导吸入麻醉剂产生的不动性的主要部位。因此，在本研究中，我们研究了改变鞘内与脑室内Na+浓度对MAC.METHODS的影响：在长期留置导管或探针制备的大鼠中，我们将Na+不足和Na+过量的溶液输注到腰蛛网膜下腔和脑室内空间，并在输注前、输注期间和输注后测量异氟烷的MAC。异氟醚的MAC与鞘内注入的Na+浓度直接相关，但与脑室内注入的浓度不相关。结论：结果与Na+通道介导或调节MAC一致。这些可能包括电压门控或配体门控通道或其他Na敏感性靶点（例如，泵、输送器、交换器）。
BACKGROUND: Previous studies demonstrated that MAC (the minimum alveolar concentration of an inhaled anesthetic that produces immobility in 50% of subjects exposed to noxious stimulation) for halothane directly correlates with the central nervous system concentration of Na+. However, those studies globally altered Na+ concentrations, and thus did not distinguish effects on the spinal cord from cerebral effects. This is an important distinction because the cord appears to be the primary site for mediation of the immobility produced by inhaled anesthetics. Accordingly, in the present study, we examined the effect of altering intrathecal versus intracerebroventricular concentrations of Na+ on MAC.METHODS: In rats prepared with chronic indwelling catheters or stylets, we infused solutions deficient in Na+ and with an excess of Na+ into the lumbar subarachnoid and intracerebroventricular spaces and measured MAC for isoflurane before, during, and after infusion.RESULTS: MAC of isoflurane correlated directly with concentrations of Na+ infused intrathecally but did not correlate with concentrations infused intracerebroventricularly.CONCLUSION: The results are consistent with a mediation or modulation of MAC by Na+ channels. These might include voltage-gated or ligand-gated channels or other Na-sensitive targets (e.g., pumps, transporters, exchangers).