The effect of some tricyclic antidepressants on the inhibition of mouse brain monoamine oxidase in-vivo by phenelzine

Abstract

Four tricyclic antidepressants, amitriptyline, imipramine, desipramine and iprindole have been shown to partially protect mouse brain monoamine oxidase in-vivo from the irreversible enzyme inhibition produced by subsequent injection of phenelzine. Levels of protection were similar when the enzyme was assayed with selective substrates (5-hydroxytryptamine and phenethylamine) for both the A and B forms of the enzyme. Although other explanations cannot at this stage be ruled out, these observations are consistent with the tricyclic antidepressants acting as reversible inhibitors of brain monoamine oxidase in-vivo.

Mitochondrial Functions in Mood Disorders

“…Five tricyclic antidepressants, amitriptyline, clomipramine, desipramine, imipramine and iprindole, have comparable potencies as inhibitors of MAO in rodent brain and liver [192]. These antidepressants have been shown to partially protect mouse brain MAO in vivo from the irreversible enzyme inhibition produced by subsequent injection of phenelzine [193]. Concentrations of tricyclic antidepressants, which showed a pronounced inhibitory effect on the MAOs activity, were significantly higher than plasma levels of the drug found under therapeutic conditions [194][195].…”