Influence of protective drugs on the EEG during short-term transient ischaemia

Influence of drugs on the cessation time of the brain electrical activity (resistance time) during total cerebral ischaemia evoked by clamping of the aorta for 50 sec; on the duration of its reappearance during reperfusion (restitution time) and on the background activity of EEG were studied. The experiments were carried out in 7 groups. Each group contained 5 animals. Nine clampings with intermittent reperfusion periods of 10 min were performed in each animal. One group served as control. In the remaining ones after the first three clampings the animals were given Glyo-6, Nootropil, Verpamil, Epanutin, Inactin or Lidocain. The resistance and restitution times measured in the control group as well as the reproductibility of the power spectrum values of the EEG provided evidence for the stability of the model. Glyo-6 in a dose of 10 mg/kg, Nootropil in a dose of 100 mg/kg or Verpamil in a dose of 0.125 mg/kg did not alter the above-mentioned parameters. As an effect of the administration of Epanutin in a dose of 10 mg/kg, the resistance time increased slightly, whereas restitution time decreased significantly. Administration of Inactin in a dose of 15 mg/kg, or Lidocain in a dose of 100 mg/kg increased considerably resistance time for a period of about one hour. The results indicate that in the initial phase of ischaemic brain damage both the cessation of EEG activity and the restitution during reperfusion after short-term occlusion of the circulation can be influenced favourable with drugs which decrease cerebral metabolism, inhibit synaptic transmission and have membrane stabilizing effect.