Cerebral Phosphoprotein Promoted by Electrical Impulses

It has been shown (Heald, 1956b) in cerebral slices that duringtherapidbreakdown ofphosphocreatine, brought about by brief passage of electrical pulses (see Heald, 1954), there is an increased exchange of phosphate between the phosphates soluble in trichloroacetic acid and those in the insoluble residue. Thus in cerebral slices which had been allowed to metabolize radioactive inorganic phosphate for a brief period, electrical pulses applied for only 10 sec. caused a decrease in the specific radioactivity of both phosphocreatine and the y-phosphate of adenosine triphosphate, and an increase in the specific radioactivity of the phosphorus of the tissue residue remaining after removal of the phosphates soluble in trichloroacetic acid. It was suggested that these changes could be resonably interpreted upon the basis of a cyclic transfer of phosphate between phosphocreatine, adenosine triphosphate and some unknown tissue phosphate or phosphates. This paper describes experiments implicating a phosphoprotein fraction in such an exchange. An account of this work was presented to the Biochemical Society in November 1956 (Heald, 1957).