Guanosine di- and tri-phosphates in the phosphate metabolism of cerebral tissues promoted by electrical pulses

Abstract

Attempts were made to isolate, from guinea pig cerebral slices metabolizing radioactive inorganic phosphate in vitro, phosphates which increase in specific radioactivity upon the passage of electrical pulses through the slices. A fraction possessing this property consisted of adenosine and guanosine di- and tri-phosphates, which were isolated and characterized. Only the guanine nucleotides increased in specific radioactivity upon the passage of pulses. No other fraction was found which showed such an increase. It is suggested that the cerebral phosphoprotein fraction previously shown to increase in specific radioactivity under similar conditions is a stable degradation product of a more labile compound which is split to other products, possibly including inorganic phosphate, under the alkaline conditions used in the present experiment.