ELECTROENCEPHALOGRAPHIC STUDIES OF XYLOPININE, 2,3,10,11-TETR AMETHOX Y-5,6-13,13a-TETRAH YDRO-8-DIBENZO(a-g) QUINOLIZINE CITRATE IN RABBIT

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Abstract
The effects of intravenous injection of xylopinine on the spontaneous EEG [electroencephlogram] recorded from the motor and sensory cortices and the archicortex were studied in the unanesthetized rabbits. One to 10 mgAg of xylopinine produced the appearance of resting waves, mainly consisted of slow frequency and high voltage, in the EEG of the motor cortex and hippocampus. The duration of the resting waves produced by the small doses was more prolonged than that produced by the large doses. The reticular and thalamic arousal responses to stimulation of the brainstem reticular formation and intralaminar nuclei of the thalamus with high frequency square waves were depressed by xylopinine. The elevation of the threshold voltage for the reticular arousal response by 1 mg/kg was 25% at 15 to 60 minutes after the injection and declined to the previous level at 2 hours, while the elevation of the same threshold at 15 minutes after 10 mg/kg was 175% and declined already to the previous level at 45 minutes. The difference of the effects of xylopinine on the threshold voltage for the thalamic arousal response between small and large doses was also observed. The recruiting or the augmenting response of the EEGs to stimulation of the centre median nucleus or the medial lemniscus with low frequency square waves was depressed by xylopinine. The elevation of the threshold voltage for both responses produced by xylopinine did not recover within several hours after the injection. Arousal responses of the cortical and hippocampal EEGs and elevation of the threshold voltage for the recruiting response to the intravenous injection of methamphetamine were almost not affected by xylopinine. The arousal responses of the EEGs of the motor cortex and hippocampus to occlusion of both common carotid arteries and intracarotid injection of epinephrine were somewhat depressed by xylopinine. The arousal responses of the EEGs of the motor cortex and hippocampus to stimulation of the posterior part of the hypothala-mus was also depressed by xylopinine. The after-seizure discharges of the hippocampla EEG produced by stimulation of the contralateral hippocampus were depressed by the small dose, while the threshold voltage of the stimulation was reduced by the large dose. The small dose of xylopinine depressed the same discharges produced by stimulation of the amygdaloid nucleus, while the large dose did not affect them.