NEUROHUMORAL FACTORS IN THE CONTROL OF 

 ANIMAL BEHAVIOUR 



K. LissAK AND E. Endroczi 



The homeostasis of the organism is regulated by two factors, neural and 

 endocrine, which, by complex niteraction, have influenced each other 

 throughout the course of evolution. 



Higher nervous activity and conditioned reflexes are also manifesta- 

 tions of the adaptability of the organism. Without wishing to disregard 

 the basic role played by neocortical structures in the development of higher 

 nervous processes, we regard it as necessary to analyse the role of sub- 

 cortical systems ui the organization of conditioned reflex connections and 

 basic emotional behaviour. 



After the discovery of the role of the difi^iise activating system in the 

 maintenance of the waking state of the cortex, a whole series of communi- 

 cations has appeared in recent years. All show that the neural network, 

 described by Cajal sixty years ago, and termed reticular formation today, 

 can be influenced not only by neural but also humorally. Therefore, 

 when the mechanisms of the brain stem are considered, the neural organi- 

 zation of the mesencephalon and diencephalon must be regarded as an 

 integrating system at a complex neurohumoral level. 



During the past decade one of the subjects investigated in our Institute 

 has been the interrelationship between complex neuroendocrine processes 

 and behaviour. The problem which, first of all, concerns the neuro- 

 endocrine control of the conditioned reflex and basic emotional behaviour 

 in higher animals, is enormously complicated by the fact that interference 

 with neural organization also affects endocrine regulation, the changes 

 of which react on the nervous system and influence behaviour. 



In our earlier investigations (Endroczi, Lissak and Telegdy, 1958) it was 

 observed that during lactation the domesticated mother rat would attack 

 and kfll a frog put in her cage. This maternal aggressivity can be observed 

 only during the period of lactation. The administration of oestrone 

 for a few days (300-400 lU/ioo g.b.w.) will abolish it completely without 

 interfering with the care of the offspring. The interesting point in this 

 experiment was that in the prevention of this folliculine action hydro- 

 cortisone was more effective than progesterone. At the same time it was 

 also observed that hydrocortisone not only abolished the inhibitory 



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