[Frequency spectrum analysis of the electrical activity of the brain in the rat as affected by ketamine]

The effect of ketamine (80 mg/kg, intraperitoneally) on the frequency composition of electrograms of the visual and somatosensory regions of the cerebral cortex, hippocampus and medial nuclei of the hypothalamus was studied in chronic experiments on rats. An increase of the power of 4 Hz fluctuations and a decrease of 6 Hz fluctuations were noted in all structures. Ten min. after the drug injection the effect of 4 Hz rhythm enhancement was sharply suppressed (except the visual cortex). A combined administration of 5-hydroxytryptophan (30 mg/kg) and alpha-methyl-dihydroxyphenylalanine (100 mg/kg) resulted in the occurrence on the visual cortex of the effects similar to those produced by ketamine.