61) Mi: TAHOl.ISM IN (.llANdi:!) C M K ll li K A L ACTIVITY 



Lc\cls of phosphociciitinc luivc been examined in rats in which 

 trauma was produced eitlier by intravenous injection of adenosine 

 triphosphate or by hind hnib iscliaemia. No tlecrease in quantities 

 was observed though here as in other experiments the use of 

 anaesthesia before drowning in hquid air might have restored 

 levels which had been depicted (Stoner and 'I'hrelfall, 1954). In 

 cats or monkeys anaesthetized with dial, although topical applica- 

 tion of strychnine to the cortex caused the distinctive " spike " 

 discharge, the levels of phosphocreatinc and adenosine triphos- 

 phate were unchanged (Dusser de Barrenne et al., 1941). It was 

 suggested that here strychnine synchronizes cellular discharges 

 rather than stimulates the cortex to greater activity than normal. 



]\laintenance of almost constant levels of adenosine triphos- 

 phate has been considered to be part of a regulatory system aimed 

 at suppressing excess convulsive activity. Thus the discharge 

 produced by topical application of acetyl choline to cat cerebral 

 cortex was suppressed by a similar application of adenosine di- or 

 triphosphate (Jordan et al., 1950; Robinson and Hughes, 1951). 

 Similar results were obtained if the adenosine derivatives were 

 injected intravenously. The latter results suggest that factors other 

 than adenyl derivatives enter into such changes for it is unlikely 

 that the transfer of adenosine triphosphate into the brain is rapid 

 vet the effects were apparent within a few seconds of injection. 



It seems likely that whether or not changes in the quantities of 

 the acid-soluble phosphates occur as a result of seizures is deter- 

 mined both by the type of convulsant used and the criteria 

 adopted in defining convulsive activity. Differences are in part 

 attributable to the speed of action of the convulsant and to the 

 extent to which the tissue suffers from a mild hypoxia. Thus, if the 

 increased blood How produced for example by admixture of 

 carbon dioxide with the inspired air can maintain the tissue in an 

 adequately oxygenated condition oxidative phosphorylation may 

 proceed at a rate such as to maintain near normal levels of phos- 

 phocreatinc, though the rate of cerebral metabolism is increased, 

 l^lectroshock, since it is applied immediately, differs from metra- 

 zole in that no lag period is needed before an effective dose is 

 built up. In such conditions stimulation of the energy consuming 

 processes is likelv to be extremelv rapid and thus to enable effects 

 to be seen before oxidative metabolism has begun to increase. 

 1 lowever, it is to be remembered that an apparent absence of effect 



