Ermens A A, Refsum H, Rupreht J, Spijkers L J, Guttormsen A B, Lindemans J, Ueland P M, Abels J
Institute of Hematology, Erasmus University Rotterdam, The Netherlands.
Clin Pharmacol Ther. 1991 Apr;49(4):385-93. doi: 10.1038/clpt.1991.45.
The effects of nitrous oxide-induced cobalamin inactivation on homocysteine and folate metabolism have been investigated. Plasma levels of cobalamin, folate, homocysteine, and methionine were determined in 40 patients before and after operation under nitrous oxide anesthesia (range of exposure time, 70 to 720 minutes). Twelve patients anesthetized with total intravenous anesthesia served as control subjects (range of exposure time, 115 to 600 minutes). Postoperative plasma levels of folate and homocysteine increased (p less than 0.001) up to 220% and 310%, respectively, in nitrous oxide-exposed patients, whereas plasma levels of methionine decreased (p less than 0.025). Response occurred after 75 minutes of nitrous oxide exposure. The percentage increase of plasma folate and homocysteine correlated significantly with exposure time (p less than 0.025 and p less than 0.0001, respectively). In eight patients receiving nitrous oxide anesthesia plasma homocysteine levels had not returned to preoperative levels within 1 week (p less than 0.01). Urinary excretion of folate and homocysteine increased during and after nitrous oxide exposure (p less than 0.01 and p less than 0.002, respectively) and correlated with exposure time (p less than 0.01 and p less than 0.005, respectively). It can be concluded that disturbance of homocysteine and folate metabolism by nitrous oxide develops with little delay and return to normal levels requires several days. Elevation of plasma homocysteine levels may therefore be used for monitoring nitrous oxide-induced cobalamin inactivation.
已对氧化亚氮诱导的钴胺素失活对同型半胱氨酸和叶酸代谢的影响进行了研究。在40例接受氧化亚氮麻醉的患者手术前后（暴露时间范围为70至720分钟）测定了血浆钴胺素、叶酸、同型半胱氨酸和蛋氨酸水平。12例接受全静脉麻醉的患者作为对照（暴露时间范围为115至600分钟）。在暴露于氧化亚氮的患者中，术后血浆叶酸和同型半胱氨酸水平分别升高（p<0.001）达220%和310%，而血浆蛋氨酸水平降低（p<0.025）。在氧化亚氮暴露75分钟后出现反应。血浆叶酸和同型半胱氨酸的升高百分比与暴露时间显著相关（分别为p<0.025和p<0.0001）。在8例接受氧化亚氮麻醉的患者中，血浆同型半胱氨酸水平在1周内未恢复到术前水平（p<0.01）。在氧化亚氮暴露期间及之后，尿中叶酸和同型半胱氨酸排泄增加（分别为p<0.01和p<0.002），且与暴露时间相关（分别为p<0.01和p<0.005）。可以得出结论，氧化亚氮对同型半胱氨酸和叶酸代谢的干扰发展迅速，恢复到正常水平需要数天时间。因此，血浆同型半胱氨酸水平的升高可用于监测氧化亚氮诱导的钴胺素失活。
