Effects of (R)-(−)-1-(benzofuran-2-yl)-2-propylaminopentane hydrochloride [(−)-BPAP] in animal models of mood disorders

(R)-(−)-1-(Benzofuran-2-yl)-2-propylaminopentane hydrochloride [(−)-BPAP] is a highly potent enhancer of impulse propagation-mediated monoamine release and an inhibitor of monoamine uptake. We evaluated the efficacy of (−)-BPAP as a drug for mood disorders by using two animal models. (1) Acute, but not chronic, administration of (−)-BPAP and imipramine significantly attenuated immobility in mice induced by forced swimming. Chronic, but not acute, administration of (−)-BPAP ameliorated the impairment of social interaction (SI) behavior following forced swimming, without affecting locomotor activity. The ameliorating effect of (−)-BPAP on the impairment of SI behavior was suppressed by dopamine receptor antagonists, which suggests that the effect was mediated through the activation of the dopaminergic system. Chronic administration of imipramine tended to attenuate the impairment of SI behavior in stressed mice, but not significantly. (2) In the olfactory bulbectomized (OB) rat, chronic (−)-BPAP treatment significantly ameliorated the impairment of SI behavior, prepulse inhibition, and tone-cue fear learning, without affecting locomotor activity in an open field and circadian activity pattern. Furthermore, (−)-BPAP tended to improve sexual dysfunction in OB rats, but imipramine had no such effect. These findings suggest that (−)-BPAP may be clinically effective in treating mood disorders, including comorbid anxiety and depression that are poorly responsive to imipramine.