Effect of antidepressant drugs on 6-OHDA-treated mice in the FST

There is growing evidence suggesting that dopamine could be indirectly involved in the appearance of behavioural effects of antidepressants. In this study, we induced a partial (over 70%) and non-reversible depletion of dopamine-containing neurons in mice by i.c.v. infusion of 6-OHDA. Then, we compared the antidepressant-like effect of drugs (citalopram, paroxetine, desipramine and imipramine) with or without dopamine depletion in the mice forced swimming test. Our results clearly show that lesion with 6-OHDA does not modify the response of mice to desipramine and imipramine, whereas dopamine depletion abolished the antidepressant-like effect of citalopram and paroxetine. It could then be suggested that antidepressant-like effect of selective serotonin reuptake inhibitors (paroxetine and citalopram) in the mice FST requires the activation of dopaminergic pathways to occur.