The distribution of adenosine triphosphate in subcellular fractions of brain tissue

Abstract

The contents of adenosine triphosphate of homogenates of normal guinea-pig brain in 0-32[image]-sucrose and of fractions derived therefrom were determined by the firefly method and compared with those of animals killed by immersion in liquid N and of animals pretreated with drugs. After a rapid initial post-mortem fall, brain adenosine triphosphate reached a relatively stable value that was unaffected by homogenization. About half of this "stable" adenosine triphosphate was recovered in a fraction consisting mainly of pinched-off nerve endings, the remainder in myelin, mitochondria and the soluble supernatant. The amount of adenosine triphosphate in the nerve-ending fraction was found to be greatly in excess of the 1:4 ratio of adenosine triphosphate to pressor amine expected if the function of adenosine triphosphate there was to bind amines, as it is believed to be in other amine-storage particles. The lack of effect on the content of adenosine triphosphate of doses of reserpine which effectively depleted the brain of. 5-hydroxytryptamine and the lack of correlation in the regional distributions of adenosine triphosphate and pressor amines are further reasons for thinking that the "stable " fraction of adenosine triphosphate studied is not mainly concerned with amine storage.