Antidepressant-like effect of the organoselenium compound ebselen in mice: Evidence for the involvement of the monoaminergic system

Ebselen [2-phenyl-1,2-benzisoselenazol-3(2H)-one] is a seleno-organic compound which possesses a potent antioxidant activity and has been shown to exert neuroprotective effects in vitro and in vivo in a variety of pro-oxidative insults. The present study investigates a possible antidepressant activity of ebselen using two predictive tests for antidepressant activity in rodents: the forced swimming test and tail suspension test. Additionally, the mechanisms involved in the antidepressant-like effect of ebselen in mice were also assessed. Ebselen (10 mg/kg, s.c.) decreased the immobility time in the forced swimming test without accompanying changes in ambulation in the open-field test. In contrast, the administration of ebselen (10–30 mg/kg) did not produce any effect in the tail suspension test. The anti-immobility effect of ebselen (10 mg/kg, s.c.) was not prevented by pre-treatment of mice with p-chlorophenylalanine (PCPA, 100 mg/kg, i.p., an inhibitor of serotonin synthesis, 4 consecutive days), NAN-190 (0.5 mg/kg, i.p., a serotonin 5-HT1A receptor antagonist) or ketanserin (5 mg/kg, i.p., a serotonin 5-HT2A/2C receptor antagonist). On the other hand, the pre-treatment of mice with prazosin (1 mg/kg, i.p., an α1-adrenoceptor antagonist), yohimbine (1 mg/kg, i.p., an α2-adrenoceptor antagonist), SCH23390 (0.05 mg/kg, s.c., a dopamine D1 receptor antagonist) or sulpiride (50 mg/kg, i.p., a dopamine D2 receptor antagonist) completely blocked the antidepressant-like effect of ebselen (10 mg/kg, s.c.) in the forced swimming test. It may be concluded that ebselen produces an antidepressant-like effect in the forced swimming test that seems to be dependent on its interaction with the noradrenergic and dopaminergic systems, but not with the serotonergic system.