About Selegiline A selective irreversible MAO-B inhibitor, Phenethylamine derivative, Antiparkinsonian agent, Antidepressant. Mechanism of Action of Selegiline Selegiline is a Monoamine oxidase enzyme inhibitor. It selectively blocks MAO-B than MAO-A at recommended dose. Selegiline inhibits the reuptake of Dopamine in to the presynaptic nerve terminal and also blocks presynaptic Dopamine receptor. This will produce Dopaminergic activity. Metabolites of Selegiline (Amphetamine and Methamphetamine) interferes the reuptake and enhances the release of neurotransmitters such as Noradrenaline, Dopamine and Serotonin and produces antidepressant effect. Antiparkinsonian action: MAO-B (Monoamine oxidase enzyme-B) in the CNS is responsible for the metabolism of Dopamine to DOPAC (3, 4 Dihydroxy-phenyl acetic acid). Selegiline binds to MAO-B and inhibits the Dopamine degradation. Selegiline produces an increase in the concentration of Dopamine in the CNS