Objective:To evaluate the effect of midazolam on sevoflurane anesthesia-induced cortical abnormal electroencephalogram waves in neonatal rats.Methods:Ten male Sprague-Dawley rats, aged 7 days, weighing 12-16 g, were used in this study.After the electrodes were correctly implanted, the electroencephalogram was continuously monitored, and 6% sevoflurane was inhaled for 3 min to induce anesthesia.The experiment was carried out in three phases.In 1st phase, 2.1% sevoflurane was inhaled for 30 min.In 2nd phase, midazolam 3 μg/g was intraperitoneally injected.In 3rd phase, flumazenil 10 μg/g was intraperitoneally injected at 60 min of 2.1% sevoflurane inhalation.Each phase lasted 30 min.The total time of convulsion wave in each phase and frequency of spike wave in the last 3 min of each phase were recorded.Results:There was no significant difference in the rate of convulsion wave and spike wave developed and total duration of convulsion wave among the three phases ( P>0.05). The frequency of spike wave was significantly decreased in 2nd phase compared with that in 1st and 3rd phases ( P<0.05). Conclusion:Midazolam can decrease the frequency of cortical spike waves induced by sevoflurane anesthesia, but produces no inhibitory effect on convulsion waves in the neonatal rats.