Feedback inhibition of brain noradrenaline neurons by tricyclic antidepressants: alpha-receptor mediation.

The use of different receptor blocking agents and single-unit recording techniques indicates that feedback inhibition of brain noradrenaline neurons by tricyclic antidepressants is mediated by presynaptic alpha-receptors. After chronic imipramine treatment, noradrenaline neurons in the locus coeruleus of rat brain remained partly depressed, in agreement with clinical data. They were, however, resistant to further inhibition by imipramine or clonidine.