Effect of adrenalin and adrenal desympathization on brain-seizure activity

The effect of adrenalin and bilateral adrenal desympathization on brain-seizure activity evoked by electrical stimulation of the dorsal hippocampus was studied in adult cats. A few days after bilateral adrenal desympathization the threshold of epileptogenic hippocampal stimulation was lowered and the duration of the evoked seizure response increased. Intravenously injected adrenalin raised the threshold of epileptogenic hippocampal stimulation. After injection of small doses of adrenalin directly into the mesencephalic reticular formation the evoked seizure activity was inhibited: The threshold of epileptogenic hippocampal stimulation was raised and the total duration of the seizure discharges reduced. It is postulated that one of the important factors limiting brain-seizure activity is an increase in the circulating blood adrenalin level.