METABOLISM IN CHANGED CEREBRAL ACTIVITY 



45 



to find any differences from normal in levels of phosphocreatine in 

 the brain of chloralosed animals. In a more recent study (Gerlach 

 et al., 1958) rats were anaesthetized with a wide variety of agents 

 and decapitated and the head allowed to fall into liquid nitrogen 



Table 7. — Quantities of Energy-rich Phosphates in the Brain of 

 Normal and Anaesthetized Animals 



Animals were drowned in liquid nitrogen before removal of the brain. 



10 min after the onset of anaesthesia. No differences were found 

 in the cerebral concentrations of phosphocreatine, adenosine 

 triphosphate, guanosine triphosphate and inorganic phosphate 

 when compared with the concentrations in the brain of rats 

 drowned in liquid nitrogen. The values were higher than those in 

 cerebral tissue from controls decapitated in the same manner. The 

 authors consider that the anaesthetic prevented the sudden break- 

 down of the phosphates in the moment of decapitation, thus 



