Litt L, González-Méndez R, James T L, Sessler D I, Mills P, Chew W, Moseley M, Pereira B, Severinghaus J W, Hamilton W K
Anesthesiology. 1987 Aug;67(2):161-8. doi: 10.1097/00000542-198708000-00002.
A recent NMR study reported the elimination of halothane from the brain of rabbits to be ten times slower than expected, based on known anesthetic solubility and cerebral blood flow. The authors conducted a study in five rats using fluorine nuclear magnetic resonance (NMR) spectroscopy to see if major pharmacokinetic discrepancies are associated with the uptake, maintenance, and elimination of halothane from the brain. The rats underwent a 60-min period of halothane anesthesia. They employed a spatially selective NMR spectroscopy technique known as surface coil "depth-pulsing" to assure that the fluorine NMR signals originated in brain tissue, and not in the scalp, muscle, adipose tissue, and bone marrow that surround the brain. After the inspired anesthetic concentration was decreased to zero, the amplitude of the fluorine NMR signal decreased to 40% of its maximum value within 34 +/- 8.0 minutes (n = 5), rather than after 7 h as in the recent study, where the fluorine signal may have contained substantial contributions from metabolites or tissues outside the brain. Fluorine was barely detectable in all of the animals 90 min after stopping the administration of halothane. The authors' results are in agreement with model calculations and several other investigations.
最近的一项核磁共振研究报告称，基于已知的麻醉剂溶解度和脑血流量，氟烷从兔脑中消除的速度比预期慢十倍。作者使用氟核磁共振波谱法对五只大鼠进行了一项研究，以观察主要的药代动力学差异是否与氟烷在脑中的摄取、维持和消除有关。这些大鼠接受了60分钟的氟烷麻醉。他们采用了一种称为表面线圈“深度脉冲”的空间选择性核磁共振波谱技术，以确保氟核磁共振信号源自脑组织，而非源自脑周围的头皮、肌肉、脂肪组织和骨髓。在吸入麻醉剂浓度降至零后，氟核磁共振信号的幅度在34±8.0分钟内（n = 5）降至其最大值的40%，而不是像最近的研究那样在7小时后，在最近的研究中，氟信号可能包含来自脑外代谢物或组织的大量贡献。在停止给予氟烷90分钟后，所有动物体内几乎检测不到氟。作者的结果与模型计算和其他几项研究一致。
