METABOLISM IN CHANGED CEREBRAL ACTIVITY 61 



in overall phosphate levels may also indicate a highly localized site, 

 or sites, of action. 



The effects of convulsions upon the metabolism of the phospho- 

 lipids is not clear. Dawson and Richter (1950<2) found that brief 

 electroshock applied to mice, reduced the relative specific radio- 

 activity of the total phospholipid phosphorus by about 11%, a 

 difference which was statistically significant. Torda (1954) ob- 

 tained reductions of a similar order when mice were treated either 

 with electroshock or with metrazole. On the other hand, Ansell 

 and Dohman (1957) w-ere unable to find any changes in the amounts 

 of radioactivity incorporated into the total phospholipid phos- 

 phorus or into the individual fractions of the cephalin group as a 

 result of convulsions induced either by electroshock or by picro- 

 toxin. At present it seems that since any changes detected were 

 small, the phosphate moiety of the phospholipids is not markedly 

 involved in changes brought about by brief convulsive activity. 

 Similar changes have been noted in the phosphoproteins and in a 

 fraction probably containing phosphatido peptides (Vladimirov, 

 1953 ; Vladimirov et al.^ 1957). Thus in rats, electrically stimulated 

 via the paws, the specific radioactivities of the phosphorus in these 

 fractions was generally considered to be higher than in unstimu- 

 lated animals, though the magnitude of the differences was small. 

 It has been shown (see p. 118) that at least one fraction (the 

 phosphoproteins) shows a markedly increased rate of incorporation 

 of phosphate during the application of an applied stimulus in vitro, 

 which suggests that failure to find appreciable changes in vivo may 

 be due to difliculties of technique rather than absence of response. 



Emotional Excitement 



Stimulation of the brain by means of convulsants is essentially a 

 vigorous procedure. In attempts to examine cerebral metabolism 

 as it is affected by more physiological stimuli, the measurements 

 have been made of the changes occurring in various phosphates as 

 a result of applying different excitatory procedures to conditioned 

 and unconditioned animals. 



Effects of excitement upon the acid soluble phosphates of brain 

 were initially reported by Le Page (1946). In rats where death was 

 induced by rapid tumbling in a drum, levels of phosphocreatine 

 and adenosine triphosphate decreased while those of inorganic 



