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RESEARCH PRODUCT

PURINE AND PYRIMIDINE NUCLEOTIDES IN THE BRAIN OF NORMAL AND CONVULSANT RATS

subject

description

— Purine and pyrimidine nucleotides were measured in the brain of normal and electroshocked rats after chromatographic separation on ion-exchange resin of mono-, di- and tri-phosphorylated derivatives. CMP, IMP and NAD did not show any significant quantitative change. Adenine nucleotides showed an abrupt change followed by a rapid return to the control value. GTP was the only purine nucleotide exhibiting a relatively slow return to its starting concentration. The greatest percentage increase after electroshock was observed in UMP, which returned to its control value only after 5 min; UDPCoenzymes (i.e. UDPA plus UDPG) showed a relatively small drop during the development of the seizure and the slowest return to the base line; UTP showed a late transistory increase above the normal level after an initial drop associated with convulsant activity. Tritiated uridine was injected intracisternally to investigate the turnover of pyrimidine nucleotides. UTP showed the highest specific radioactivity at the earliest time, followed by UMP, UDPCoenzymes and CMP. It was found that convulsant activity is associated with dramatic changes in the specific radioactivity of pyrimidine nucleotides.