Chronic desipramine treatment increases activity of noradrenergic postsynaptic cells

Chronic administration of tricyclic antidepressant drugs has been shown to exert multiple influences on various mechanisms of noradrenergic nervous systems. To determine the overall effect of these influences, this study examined the effect of long-term desipramine administration on the firing rate of noradrenergic postsynaptic neurons, specifically, those in the rat hippocampus that were inhibited by the nucleus locus coeruleus. Daily injections for 3 weeks of 5 or 10 mg/kg desipramine resulted in a 32% or 49% increase, respectively, of hippocampal cell activity, suggesting that long-term desipramine treatment is antagonistic to noradrenergic functions.