The Effect of Certain Psychotropic Drugs on Arousal Responses in Rats' EEG

Abstract

Effect of four psychotropic drugs on arousal responses evoked by the reticular or hypothalamic stimulation in curarized unanesthetized rats was investigated and following results were obtained. 1) Pentobarbital sodium and meprobamate mainly inhibited the reticular activating system, while chlorpromazine hydrochloride and chlordiazepoxide hydrochloride inhibited the hypothalamic-activating system more intensely. 2) Pentobarbital sodium and chlorpromazine hydrochloride elevated the thresholds of neocortical arousal response as well as hippocampal one evoked by the stimulation of reticular formation or hypothalamus. Meprobamate and chlordiazepoxide hydrochloride, however, inhibited the development of hippocampal thetha waves caused by the stimulation of hypothalamus or reticular formation and elicited the neocortical arousal response simultaneously. 3) The results obtained suggest that the rat can be utilized for screening of psychotropic drugs which affect the central nervous system including the limbic system.