64 METABOLISM IN CHANGED CEREBRAL ACTIVITY 



of phosphocreatine decreased. Levels of inorganic phosphate were 

 raised. The magnitude of these changes depended upon the extent 

 of the initial injury and the distance from the injured portion of 

 the tissue at which the second sample was taken. Changes of this 

 type may explain the results of Shideman and Seevers (1953) who 

 found that the levels of phosphocreatine in monkey brain were 

 apparently much lower than in any other animal. The animals had 

 been subject to operation for the removal of the calvarium the day 

 before the fixation of the brain in liquid air. 



Cerebral phosphates are also changed in virus infection. Thus 

 in the infant mouse brain intracereb rally inoculated with Lancing 

 poliomyelitis virus and drowned in a carbon dioxide/ethanol 

 mixture when paralysis commenced, the levels of phosphocreatine 

 had decreased by half while adenosine triphosphate had increased 

 by 50%. All other acid-soluble phosphates showed a marked 

 decrease (Kabat, 1944). The rate of incorporation of intravenously 

 injected radioactive phosphate into different areas of the monkey 

 brain, similarly infected, showed no change from normal until 

 clinical symptoms of paralysis appeared. Thereafter increased 

 incorporation was observed first in the pons and medulla, spread- 

 ing to the cerebellar tissues as the infection became more acute 

 (Anderson, et al, 1950). It would appear that infection is accom- 

 panied by an increased turnover of phosphorus probably as the 

 result of the increased synthesis of energy-rich phosphates which 

 are presumably used in increased virus production. 



Effects of the toxic trialkyl tin compounds have been examined 

 by Stoner and Threlfall (1958). These compounds cause a signifi- 

 cant interstitial oedema of white matter and the spinal cord 

 (Magee et al.y 1957). In cerebral slices taken from poisoned 

 animals the oxygen uptake is reduced (Cremer, 1957). In rats 

 given a lethal dose of triethyl tin sulphate, after which they survive 

 for about 48 hr, it was found that the amount of radioactive 

 phosphate entering the brain was reduced. The specific radio- 

 activity of cerebral inorganic phosphate and of diphosphopyridine 

 nucleotide was lowered, but no changes were detected within 

 24 hr in the specific radioactivities of phosphocreatine or adenosine 

 di- and triphosphates. The quantities of these phosphates in the 

 brain were not affected. On the other hand, marked and significant 

 decreases were found both in the quantity and specific radioactivity 

 of the total lipid phosphorus. In this latter respect the action of 



