Involvement of the sigma1 receptor in the antidepressant-like effects of fluvoxamine in the forced swimming test in comparison with the effects elicited by paroxetine

We studied the involvement of the sigma1 receptor in the antidepressant-like effects of the selective serotonin reuptake inhibitor (SSRI) fluvoxamine in DBA/2 mice using the forced swimming test. The effects of the selective sigma1 receptor antagonist N-[2-(3,4-dichlorophenyl)ethyl]-N-methyl-2-(dimethylamino) ethylamine (BD1047) at 1 mg/kg significantly antagonized the anti-immobility elicited by fluvoxamine (10 mg/kg). However, the anti-immobility effects elicited by another SSRI, paroxetine (5 m/kg), were not altered by BD1047. The selective sigma1 receptor agonist 2S-(2α,6α,11R⁎)-1,2,3,4,5,6-hexahydro-6,11-dimethyl-3-(2-propenyl)-2,6-methano-3-benzazocin-8-ol ((+)SKF-10047) elicited dose-dependent anti-immobility effects in DBA/2 mice. BD1047 significantly blocked the anti-immobility effects induced by (+)SKF-10047 at 10 mg/kg. These results suggested that the sigma1 receptor was associated with fluvoxamine-induced antidepressant-like effects but not with paroxetine-induced antidepressant-like effects.