Acute effects of a khat extract on the rat electroencephalogram

Rats chronically implanted with cortical screw electrodes were treated with three different oral doses of a Khat extract and the EEG recorded for 5 h. Several abnormalities in EEG patterns were observed, particularly after the administration of the largest dose (400 mg/kg). Spectral analysis of EEG showed a significant shift of frequencies towards faster, lower voltage activity following administration of the two smaller doses (50 and 100 mg/kg), reflecting a stimulant effect of the extract. The highest degree of cortical activation was observed following administration of the smallest dose. With the largest dose, an initial activation was followed by a state of EEG depression characterized by a high percentage of slow, high voltage waves. It is concluded that Khat extract in small doses has a stimulant effect on the rat brain, but with larger doses induces a state of depression.