Inhibitory effect of intrahippocampal noradrenaline and isoprenaline on rabbit EEG

Influence of noradrenaline, or isoprenaline injected into the dorsal hippocampus on electroencephalogram and behavior of rabbit was studied. The injections increased the participation of slow waves and spindles in cortical EEG, suppressed hippocampal theta rhythm and blocked the spontaneous locomotor activity. The inhibitory effect of isoprenaline was reduced by intrahippocampal pretreatment with propranolol or sotalol; the beta-blockers injected intrahippocampal induced EEG arousal and behavioral excitation. These results indicate an inhibitory role of noradrenaline and isoprenaline in the hippocampus of rabbit.