Sevoflurane, enflurane and isoflurane have no persistent postanaesthetic effects on the central nervous system in cats.

Several reports have appeared on postanaesthetic convulsive disorders in humans after enflurane and isoflurane anaesthesia. However, it is controversial if enflurane induces epileptiform electroencephalogram (EEG), abnormal behaviour, or both, lasting for several days after anaesthesia in laboratory animals. We chronically implanted electrodes for EEG recording in the cortex, medial amygdala and dorsal hippocampus, and for reticular multi-unit activity (R-MUA) in the midbrain reticular formation in five cats. Two weeks later they were anaesthetized with 5.0% sevoflurane, 3.5% enflurane or 4.8% isoflurane for 3-4 h. EEG recordings, R-MUA and behaviour were observed for 1-3 h, during both wakefulness and sleep, every day for 5-7 days after anaesthesia. None of the cats showed abnormal behaviour, or EEG or R-MUA abnormalities after any of the anaesthetics, not only during wakefulness but during slow-wave and paradoxical phases of sleep. These results suggest that if seizures occur after anaesthesia, volatile anaesthesia itself may not be the cause.