Anti‐immobility activity of different antidepressant drugs using the tail suspension test in normal or reserpinized mice

Abstract

Summary— The tail suspension test is a screening procedure recently used in mice to detect antidepressant activity of drugs. The ability of amine re‐uptake inhibitors to decrease immobility in non‐reserpinized and in reserpinized mice was studied. Reserpine (4 mg/kg ip) was injected 4 h previously. Anti‐depressants were administered ip, 60 min before tail suspension. Animal activity was recorded for 6 min. Preferential serotonin re‐uptake blockers (fluoxetine, fluvoxamine, clomipramine) were poorly active in non‐reserpinized mice and inactive in reserpine‐treated mice. Noradrenergic drugs (desipramine, demexiptiline, viloxazine) were more efficient in reserpinized than in non‐reserpinized mice. The mixed serotonin‐ noradrenaline re‐uptake inhibitor (imipramine) shows an activity which should be considered between serotonin re‐uptake inhibitors and noradrenaline re‐uptake inhibitors. DA re‐uptake inhibitors (amineptine, GBR 12909) exhibited the highest anti‐immobility effect in non reserpinized animals but were of low efficacy after reserpine treatment. Amphetamine differed from dopamine re‐uptake inhibitors by its better activity in reserpinized animals. Moreover, it was the only drug showing an equal anti‐immobility effect in non reserpinized and reserpinized mice because the dose of 8 mg/kg of amphetamine reduced immobility in reserpinised mice with the same intensity as the dose of 4 mg/kg in non reserpinised mice whereas no other drugs tested in this study achieved the same effect. Comparison of anti‐immobility activities of putative antidepressants in non‐pre‐treated and in reserpine‐pre‐treated mice, using the tail suspension test, may be useful to discriminate amphetamines from antidepressant drugs and to differentiate between categories of amine re‐uptake blockers.