THE INFLUENCE OF INHALATIONAL ANESTHETICS ON THE ENERGY METABOLISM AND CREATIN KINASE SYSTEM OF BRAIN DURING BRAIN ISCHEMIA

我们之前报道过，与异氟醚（Iso）和七氟醚（Sev）麻醉相比，氟烷（Hal）延迟了大鼠模型脑缺血后脑细胞内pH （pHi）和[ATP]的恢复。我们没有发现[无机P]和[磷酸肌酸（PCr）]的回收率有任何差异，因此我们假设Hal影响了肌酸激酶（CK）正向反应（PCr+ADP→Cr+ATP）。方法：采用磁共振波谱技术，进一步观察Hal对脑缺血时及缺血后脑组织能量代谢的影响是否呈剂量依赖性。Wistar大鼠分为3组：1% Hal、2% Hal和1.5% iso处理组（n=7）。通过双侧颈动脉结扎和抽血治疗脑缺血9分钟后，我们继续观察至2小时。用磁共振饱和转移技术测定了常压条件下Hal/Iso麻醉下CK正反应的准一级速率常数（kf）。结果：将Wistar大鼠分为2组，Hal与Iso组比较，延迟了pHi和[ATP]的恢复，但两组之间没有剂量依赖性。两种麻醉条件下kf值差异无统计学意义（Hal组为0.24±0.05，Iso组为0.30±0.04）。结论：氟烷可能破坏脑能量平衡，氟烷对神经麻醉有不良作用，有脑缺血的危险。

We previously reported that halothane (Hal) delayed the recoveries in cerebral intracellular pH (pHi) and [ATP] in comparison with isoflurane (Iso) and sevoflurane (Sev) anesthesia after cerebral ischemia in the rat model. We did not find any differences in the recoveries in [inorganic P] nor [phosphocreatine (PCr)], therefore we hypothesized that Hal affected the creatine kinase (CK) forward reaction (PCr+ADP→Cr+ATP).METHODS : With using magnetic resonance spectroscopy, we further investigated whether Hal affected the brain energy metabolism during and after cerebral ischemia dose-dependently. Wistar rats were divided into 3 groups : 1% Hal-, 2% Hal-, or 1.5% Iso-treated (n=7). After 9 min of cerebral ischemia by bilateral carotid ligation and blood withdrawal, we continued the observation up to 2 hrs. We then measured the pseudo first-order rate constant (kf) of CK forward reaction in Hal/Iso anesthesia determined by MR saturation transfer technique under normoxic condition.RESULTS : Wistar rats were divided into 2 groups Hal delayed the recoveries in pHi and [ATP] in a comparison with Iso group but in the two Hal groups, we could not find the dose-dependent effect between 2 Hal groups. There were no differences between the both anesthetic conditions but significant difference in the values of kf (0.24±0.05 in Hal and 0.30±0.04 in Iso anesthesia).CONCLUSION : Halothane might impair the brain energy balance and we concluded that halothane has an undesirable property for neuroanesthesia with the risk of cerebral ischemia.