Selegilin Exerts Antidepressant-Like Effects During the Forced Swim Test in Adrenocorticotropic Hormone–Treated Rats

In the present study, we investigated the effect of adrenocorticotropic hormone (ACTH) on the immobilization of rats in the forced swim test after the administration of selegiline, a selective and irreversible monoamine oxidase (MAO)-B inhibitor. Single and repeated administration of selegiline significantly decreased the duration of immobility in normal rats. When selegiline was administered for 15 days, we observed a significant decrease in immobility in rats treated with ACTH for 14 days. The immobility-decreasing effect of selegiline was blocked by nafadotride, a selective dopamine D3–receptor antagonist in normal and ACTH-treated rats. Selegiline may be useful in an animal model of depressive conditions resistant to tricyclic antidepressant treatment via the dopamine D3receptor. Keywords:: selegiline, monoamine oxidase-B, treatment-resistance depression, forced swim test, dopamine D3receptor