Central nervous system effect of enflurane.

实验是在猫和老鼠身上进行的。在安氟醚麻醉（2-5%）的猫中，低碳酸血症（PaCO2;20mmHg）不诱发脑电图癫痫发作，而在刺激（轻拍前肢）时，当安氟醚高于3.5%时，正常碳酸血症或低碳酸血症均诱发癫痫发作。诱发癫痫发作所需的刺激呈剂量依赖性降低。单侧大脑皮质切除未改变丘脑的脑电图。皮层脑电图也不受丘脑和海马腹底复合体（VB）破坏的影响。诱导癫痫发作所需的刺激不受海马破坏的影响，但由于VB破坏而增加。在安氟醚麻醉下，坐骨神经电刺激引起的体感诱发电位在皮质和丘脑中呈剂量依赖性抑制，不受皮质切除的影响。另一方面，安氟醚增加电诱发癫痫发作的阈值，并剂量依赖性地抑制药物（戊四唑、卡因酸、青霉素）引起的癫痫发作。此外，深度安氟醚麻醉消除了皮质内注射青霉素引起的大鼠VB、大脑皮层、胼胝体和内囊葡萄糖消耗的增加，而单独安氟醚（4%）在这些区域产生了特征性的增加。即使在前肢轻拍引起癫痫发作时，也没有观察到猫的胼胝体和海马CA3中葡萄糖消耗的增加。4%安氟醚麻醉时，局部脑血流量明显增加，低碳酸血症使局部脑血流量减少，可能导致代谢与脑血流不耦合。综上所述，在深度安氟醚麻醉过程中，体感刺激诱导癫痫发作，而电或药物诱导的癫痫发作被抑制，提示安氟醚具有致痫和抗癫痫的特性。结果还显示了安氟醚麻醉时大脑皮层和皮层间活动的物种差异。少

Experiments were performed in cats and rats. In cats anesthetized with enflurane(2-5%), eeg seizures were not induced by hypocapnia(PaCO2;20mmHg), while with stimulation(tapping forelimb), seizures were induced either at normocapnia or hypocapnia when enflurane was above 3.5%. The stimulation required to induce seizures was dose-dependently decreased. Unilateral excision of cerebral cortex did not change EEG in the thalamus. Cortical EEG was not also affected by a destruction of ventrobasal complex(VB) in the thalamus and of the hippocampus. Stimulation required to induce seizures was not affected by a hippocampal destruction but was increased by a VB destruction. Somatosensory evoked petentials in the cortex and thalamus by an electrical stimulation of sciatic nerve during enflurane anesthesia were dose-dependently suppressed, and were not affected by cortical excision.Enflurane, on the other hand, increased threshold of electrically induced seizures and dose-dependently suppressed th … More e seizures induced by drugs (pentylenetetrazol, kainic acid, penicillin). Furthermore, deep enflurane anesthesia abolished the increase of glucose consumption in the VB, cerebral cortex, corpus callosum and internal capsule produced by intracortical injection of penicillin despite enflurane(4%) alone produced characteristic increase in these areas in rats. The increase in glucose consumption in the corpus callosum and hippocampal CA3 was not observed in cats even when seizures were induced by forelimb tapping. Local cerebral blood flow was markedly increased during 4% enflurane anesthesia, which was decreased by hypocapnia, possibly producing uncoupling between metabolism and flow.In summary, somatosensory stimulation induces seizures during deep enflurane anesthesia, while electrically or drug-induced seizures are suppressed, suggesting epileptogenic and antiepileptic properties of enflurane. The results also demonstrated the species difference in cerebral cortical and intercortical activities during enflurane anesthesia. Less