Effects of Imipramine and Bupropion on the Duration of Immobility of ACTH-Treated Rats in the Forced Swim Test: Involvement of the Expression of 5-HT_2A Receptor mRNA

Abstract

We examined the effect of chronic administration of imipramine and bupropion, monoamine reuptake inhibitors, on the duration of immobility in the forced swim test and serotonin (5-HT)_2A receptor function in the form of 5-HT_2A receptor mRNA levels in rats chronically treated with adrenocorticotropic hormone (ACTH). The immobility-decreasing effect of bupropion without imipramine did not influence the chronic ACTH treatment. The effect on the expression of 5-HT_2A receptor mRNA of chronic ACTH treatment was decreased by bupropion, but not imipramine. These results suggest that bupropion has the effect of reducing immobility time in the forced swim test in the tricyclic antidepressant-resistant depressive model induced by chronic ACTH treatment in rats, and that decreased 5-HT_2A receptor mRNA levels may be involved in this phenomenon.