Observations concerning adrenergic functions and antidepressant activity: Pharmacological, biochemical and clinical results with a new imidazo-quinazoline derivative¹

Abstract

The paper deals with an imidazo-quinazoline derivative showing a pharmacological activity spectrum similar to that of the tricyclic antidepressants, i. e., inhibition of spontaneous activity with increased excitability, tetrabenazine antagonism, and potentiation of the catecholamine effects. Monoaminoxydase inhibition could not be demonstrated biochemically. The Compound inhibited the cerebral storage capacity for 7 H3-norepinephrine applied by intraventricular and intracisternal routes, and changed the metabolite spectrum in the brain in a similar manner to that of desmethylimipramine and amphetamine. Otherwise there was no evidence for an amphetamine-like effect. The substance differs from the known tricyclic Compounds in that it possesses no anticholinergic and arousal inhibiting components. In depressive patients an activating and anti-inhibitory, but no mood-lightening effect could be detected. The substance is clinically very similar to the monoaminoxydase inhibitors. The mood-lightening effect of the antidepressants cannot be sufficiently explained by the catecholamine potentiation.