Norepinephrine Turnover and Metabolism in Rat Brain after Long-Term Administration of Imipramine

Science  15 May 1970:
Vol. 168, Issue 3933, pp. 867-869
DOI: 10.1126/science.168.3933.867


The rate of disappearance of intracisternally administered tritiated norepinephrine from rat brain is decreased after a single dose of the tricyclic antidepressant imipramine. During long-term administration of imipramine, however, the rate of disappearance of tritiated norepinephrine from brain gradually increases, and there is a concurrent decrease in the content of endogenous norepinephrine in brain. These findings may help to explain why antidepressant effects are observed clinically only after long-termn treatment with imipramine.