Zhao M, Fortan L G, Evelhoch J L
Department of Internal Medicine, Wayne State University School of Medicine, Detroit, Michigan, USA.
Magn Reson Med. 1995 May;33(5):610-8. doi: 10.1002/mrm.1910330505.
The principal aim of these studies was to evaluate the utility of isoflurane and halothane for NMR investigations of tumor physiology. In vivo 31P and 2H NMR were used to examine RIF-1 tumors before, during, and (for 31P) after anesthesia. In tumors, halothane decreases blood flow, [PCR]:[NTP], and pH indicated by the Pi chemical shift (pHnmr), while it increases [Pi]:[NTP]; effects consistent with well-established cardiovascular effects of halothane. Isoflurane does not affect tumor blood flow or [PCr]:[NTP], but increases tumor [Pi]:[NTP] and decreases tumor pHnmr. In vivo 31P NMR measurements of normal mouse liver (upper abdomen) indicate that isoflurane has a similar effect in the liver. Although the mechanism for these effects is unknown, observation of a split Pi peak during isoflurane anesthesia suggests that a pool of Pi in a lower pH environment may become evident under isoflurane anesthesia. Regardless of the cause for increased [Pi]:[NTP] and decreased pHnmr, the utility of isoflurane anesthesia for 31P NMR studies of energy metabolism is limited.
这些研究的主要目的是评估异氟烷和氟烷在肿瘤生理学核磁共振研究中的效用。在活体中，利用³¹P和²H核磁共振在麻醉前、麻醉期间以及（针对³¹P）麻醉后对RIF-1肿瘤进行检查。在肿瘤中，氟烷会降低血流量、[磷酸肌酸]：[核苷三磷酸]以及由无机磷酸盐化学位移（pHnmr）所指示的pH值，同时会增加[无机磷酸盐]：[核苷三磷酸]；这些效应与氟烷已确定的心血管效应一致。异氟烷不影响肿瘤血流量或[磷酸肌酸]：[核苷三磷酸]，但会增加肿瘤的[无机磷酸盐]：[核苷三磷酸]并降低肿瘤pHnmr。对正常小鼠肝脏（上腹部）进行的活体³¹P核磁共振测量表明，异氟烷在肝脏中具有类似效应。尽管这些效应的机制尚不清楚，但在异氟烷麻醉期间观察到无机磷酸盐峰分裂表明，在异氟烷麻醉下，处于较低pH环境中的无机磷酸盐池可能会变得明显。无论[无机磷酸盐]：[核苷三磷酸]增加和pHnmr降低的原因是什么，异氟烷麻醉在³¹P核磁共振能量代谢研究中的效用都是有限的。
