Evidence for the locus coeruleus involvement in desipramine action in animal models of depression

Desipramine (DMI) effectively antagonized hypothermia induced by reserpine and clonidine in rats. DMI effects were attenuated or even abolished after electrolytic or 6-hydroxydopamine-induced lesion of the locus coeruleus (LC) as well as by administration of DSP-4 (N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine), a selective noradrenergic neurotoxin. Contrary to the LC lesions, electrolytic destruction of the ventral noradrenergic bundle did not change DMI action but antagonized reserpine-induced hypothermia by itself. Our results underline a possible involvement of the LC system in mechanism of antidepressive action, which was suggested previously in this laboratory.