Norepinephrine Pools in Rat Brain: Differences in Turnover Rates and Pathways of Metabolism

• Published in: Science (American Association for the Advancement of Science) Vol. 172; no. 3983; pp. 587 - 589
• Main Authors: Schildkraut, Joseph J., Draskoczy, Paul R., Lo, Pallas Sun
• Format: Journal Article
• Language: English
• Published: United States American Association for the Advancement of Science 07.05.1971
• Subjects: Biochemical pathways; Brain; Brain - metabolism; Brain Chemistry; Cisterna Magna; Electroconvulsive therapy; Electrodes; Injections; Intravenous injections; Metabolism; Nerves; Neurons; Norepinephrine; Norepinephrine - administration & dosage; Norepinephrine - metabolism; Normetanephrine; Normetanephrine - metabolism; Time Factors; Tritium
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.172.3983.587

The rate of disappearance of intracisternally administered [$^{3}$H] norepinephrine from rat brain gradually declines as a multiphasic exponential function of time. Conversion to [$^{3}$H] normetanephrine accounts for a larger fraction of the [$^{3}$H] norepinephrine released in the brain shortly after its intracisternal injection than that released at later times. Pools of norepinephrine in the brain thus appear to differ in their turnover rates and pathways of metabolism. The pool of norepinephrine with a rapid rate of turnover and an appreciable conversion to normetanephrine, identified by the techniques reported here, may correspond to a pool of newly synthesized norepinephrine in the brain.