CHAPTER L XXVI I 



Metabolism of the central nervous system in vivo 



LOUIS SOKOLOFF Xational Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 



CHAPTER CONTENTS 



Methods 



Simple Behavioral-Chemical Correlation Techniques 

 Tissue Content and Incorporation Techniques 

 Arteriovenous Differences 



Combination of Blood Flow and Arteriovenous Differences 

 Polarographic Techniques 

 Characteristics of Normal Metabolism of the Central Nervous 

 System in vivo 

 Normal Substrates and Products 

 Normal Metabolic Rate 



Evidence for Obligatory Aerobic Utilization of Glucose by 

 the Central Nervous System 

 Impairment of central nervous system activity produced 



by glucose deprivation 

 Recovery from effects of hypoglycemia produced by 



glucose administrations 

 Relative inability of other substrates to produce recovery 

 from effects of hypoglycemia 

 Miscellaneous Substances of Importance in Metabolism of 

 the Central Nervous System 

 Physiological Interrelationships of Metabolism of the Central 

 Nervous System 

 Relationship of Cerebral Metabolism to Circulation 

 Relationship of Cerebral Metabolism to Growth, Develop- 

 ment and Age 

 Relationship between Metabolic Rate and Functional 



Activity in the Central Nervous System 

 Effects of Altered Body Temperature on Cerebral Metabolic 

 Rate 

 Metabolism of the Central Nervous System in Various Patho- 

 logical States 

 Inadequate Nutrient Supply 

 Circulatory deficiency 

 Oxygen deficiency 

 Glucose deficiency 

 Intracellular Defects 



Systemic metabolic disease 

 Anesthesia 

 Convulsive disorders 

 Miscellaneous disorders 

 Effects of Hormones and Drugs on in vivo Metabolism of the 

 Central Nervous System 



Hormones and Related Drugs 



Thyroid hormone 



Pituitary, adrenal cortical and sex hormones 



Adrenal medullary hormones 

 Psychosomimetic and Tranquilizing Drugs 



an understanding of the normal patterns of metabo- 

 lism and their relation to function is in the case of the 

 central nervous system probably more dependent on 

 the results of in vivo studies than in any other system 

 of the body. Because of its role as a communications 

 system, the functioning of the central nervous system 

 is completely integrated with the various activities 

 going on within its own various parts, in other parts 

 of the nervous system and in almost all other struc- 

 tures of the both, furthermore, the major portion 

 of the central nervous system, the brain, is involved in 

 the unique processes which subserve the phenomenon 

 of consciousness. It is impossible to conceive of either 

 of these functions, communications or consciousness, 

 and their supportive metabolic processes operating 

 under the isolated conditions required by in vitro 

 experiments. 



Furthermore, certain unique features of the metabo- 

 lism of the central nervous system amplify the im- 

 portance of in vivo studies. Its normal functions are 

 completely dependent on the obligatory consumption 

 of oxygen and glucose, and its metabolic rate is 

 normally very great, particularly in relation to its 

 stores of these essential nutrients. It is, therefore, 

 dependent on a continuously adequate renewal of 

 these nutrient materials by means of a relatively 

 enormous blood flow, approximately 55 ml per 100 

 gra per min., and interruption of these supplies 

 rapidly leads to impairment of function and irrevers- 



1843 



