Synthesis of Deuterium- or Tritium-Labeled Norepinephrine and Evaluation of Its Biological Activity

A labeled norepinephrine analogue was prepared by bromination of norepinephrine with subsequent debromination with tritium or deuterium gas. The yield of tritiated norepinephrine was 10–20% with a molar radioactivity of 27 Ci/mmol. The biological activity of tritiated norepinephrine was evaluated by analyzing its specific capture by noradrenergic neutrons in thick sections of the brainstem and midbrain of Wistar rats, and in a suspension of cells of pheochromocytoma PC12 expressing the membrane transporter of norepinephrine. It is shown that tritium-labeled norepinephrine synthesized by the proposed method does not differ in biological activity from the natural norepinephrine.