Effect of various antidepressive agents on brain monoamine oxidase activity

The effect of different antidepressants (MAO inhibitors, monoamine uptake inhibitors, new drugs) on the activity of bovine brain monoamine oxidase was investigated. The type A MAO activity was found to be selectively inhibited by the morpholine derivative, moclobamide (IC50-10(-5) M). Pyrazidol, inkazan, imipramine, and iproniazide also had an inhibitory effect on the enzyme activity, but their action was not selective. Zymelidine and norzymelidine (10(-4) M) slightly reduced the deamination of serotonin and 2-phenylalanine. The hydrazine derivatives, N 33 and N 34 showed the same effects. The morpholine derivative, viloxazine had no effect on the MAO activity of bovine brain. It is inferred that not only classic MAO inhibitors but also antidepressants of different structure are capable of inhibiting brain monoamine oxidase.