Abstract

Background: Previous studies have indicated that major depressive disorder and anxiety disorders are associated with inflammatory progressions. It has also been shown that administration of anti-inflammatory drugs improve the patient’s psychiatric condition. These facts suggest that NSAIDs may be used as an adjunctive therapy in the management of depression. Herein, we investigated whether a combination of suboptimal dose of the selective serotonin reuptake inhibitor, fluoxetine, with aspirin improves the anti depressive effects of fluoxetine.

Methods: Both mouse forced swim and tail-suspended mice, as models of animal depression, displayed respectively, inactive floating position, decreased active swimming and immobility behavior. In these models, mice were treated with single optimal (20mg/kg, ip) or suboptimal (5mg/kg, ip) doses of fluoxetine 30min prior to running experiment.

Results: In contrast to fluoxetine treatment using 20mg/kg, a suboptimal dose induced no significant changes in the immobility duration time, active swimming and climbing trials. Interestingly, co-administration of 400mg/kg of aspirin significantly increased the reduction in immobility duration time in both models. This effect coincided with a significant increase in active swimming. In a subsequent experiment, the anti-immobility effect of this combined treatment was not associated with increase mouse general locomotor activity.

Conclusion: These findings clearly demonstrate that aspirin potentiates the beneficial effects of fluoxetine and that psycho stimulant effect does not contribute to the antidepressant value in this mouse model of depression.

Keywords: Fluoxetine; Aspirin; Depression; Forced swim test; Tail suspension test; Mouse