Central noradrenergic adaptation to long-term treatment with imipramine in rhesus monkeys

Rhesus monkeys were treated with the antidepressant drug imipramine; cerebrospinal fluid norepinephrine and dopamine-beta-hydroxylase were measured to assess central noradrenergic activity. Large changes occurred after short-term, but not long-term, treatment. Biochemical stabilization occurs at the time when therapeutic effects are seen in patients.