CHAPTER X L V I 



Central nervous regulation of body temperature 



GUNNAR STROM ' Depmtmenl of Clinical Physiology, Akademnka Sjuklmset, I Uppsala, Sweden 



CHAPTER CONTENTS 



General Considerations 

 Experimental Methods 



Stereotaxic Techniques for Acute and Chronic Experiments 



Chronic Implantation Techniques 



Indirect Thermal Stimulation of Brain 



Temperature Measurements 

 Hypothalamic Thermoceptive Structures 



Existence and Localization 



Mechanism of Activation of Thermodetectors 

 Central Integrative Structures 



Effects of Stimulation 



Effects of Chronic Destruction 

 Thermoregulatory Effector Systems 



Respiration 



Cutaneous Blood Flow 



Sweating, Salivation and Piloerection 



Shivering 



Humoral Effector Systems 



Body Water Movements 



Cerebral and Spinal Pathways of Effector Systems 

 Temperature Regulation Under Abnormal Conditions 



Effect of Anesthesia 



Fever 



Hypothermia 

 Age and Species Differences in Temperature Regulation 



Ontogenesis of Central Temperature Regulation 



Phylogenesis of Central Temperature Regulation 



Regulation in Intact Man 

 Interaction of Peripheral and Central Factors in Temperature 

 Regulation 



CENTRAL NERVOUS temperature resulation lias Ijeen 

 the subject of intensixe physioloe;ic investigation, with 

 many sided experirnental approaches, for more than 

 seventy years. Several extensive monographs or re- 

 views (9, II, 19, 27, 36, 57, 59,67, 103, 107, no, 151, 

 167, 172, 174, 193, 210) have been published which 

 have direct or indirect bearing on this subject. The 

 present description will rely for many details as well 



as main conceptions on these monographs. Emphasis 

 will be laid on function rather than structure or 

 localization of the central nervous thermoregulatory 

 mechanisms. Controversial evidence will be discussed 

 inainlv when such discussion seems important for 

 general evaluation of results, or when it exemplifies 

 important methodological problems. The text is 

 illustrated by figures chosen from various original 

 reports. A close study of experimental technique and 

 evaluation of results in such figures is believed to be a 

 valuable complement to the written description. 



GENERAL CONSIDERATIONS 



The homeothermic or warm-blooded animal keeps 

 its body temperature within a few degrees C, a mean 

 level usually around 37° to 38°C. Homeothermia is 

 accomplished to some extent by local responses of 

 thermoregulatory effector systems to local tempera- 

 ture changes, and to a greater extent by systemic 

 responses. The .systemic regulation involves: a) infor- 

 mation about the body temperature, signalled to the 

 central nervous system for receptive mechanisms 

 situated partly in the surface layers and partly in the 

 central layers of the body; h) nervous integration ol 

 such afferent signals, displayed at different levels of the 

 central nervous system; and c) reactions of different 

 effector systems, set into action by efferent nervous 

 or humoral signals, which serve to counteract the 

 initial change of surface or deep temperature (homeo- 

 static effector response). 



The skin and inucous membranes contain tempera- 

 ture receptors (103, 104), the majority of which are 

 cold receptors, each having a characteristic tempera- 

 ture below 37°C for maximum activity. The minority 

 show a maximum activity above 37°C and are there- 



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