EFFECTS OF INTRAVENTRICULARLY ADMINISTERED ADRENALINE ON RABBIT'S EEG AND THEIR MODIFICATIONS BY ADRENERGIC BLOCKING AGENTS

摘要

References(16) Cited-By(6) One of the difficulties to give the exact information on the pharmacological effects of catecholamines and the related sympathomimetic amines in the central nervous system is the not-easy access of the amines through the blood-brain barriers. Although many investigators have postulated the manifestation of the arousal waves of the EEG in response to the systemically administered adrenaline, there are many controversies whether the effects are direct or not (1). There have been reports showing that the systemically administered adrenaline produced a deactivation of the spontaneous EEG (2, 3). On the other hand, it is well-known that the direct application of adrenaline to the brain structure such as the injection of the amines into the cerebrospinal fluid produces the sleep-like behaviors and analgesia in animals (4-8). In accord with the behavioral responses the dogs are shown to exhibit the sleep pattern in the spontaneous EEG (8). Taking advantage of the easy penetration of catecholamines through the blood-brain barriers in the kitten and the chiken, the effects of catecholamines on the behavior and the EEG have been studied (9). Based on the responses of the infant animals to the amines, the adrenergic receptor in the central nervous system has also been discussed (11). There is no assurance, however, that the changes in EEG and behavior produced by catecholamines administered intraventricularly in the adult animals and systemically in the infant animals are brought about by the similar mechanism. Therefore, the generalization of catecholamine classification and receptor hypothesis in the central nervous system based on the experiments in infant animals could not be accepted so simply. Moreover, the mode and the site of action of catecholamines thus administered can not be clearly answered. In the present experiment, effects of intraventricularly administered adrenaline to the EEG and the possibility of their modifications by adrenergic blockers were examined in rabbits in order to gain some informations on the mode and the site of action of the amines.