ENHANCEMENT OF IMMOBILITY IN MOUSE FORCED SWIMMING TEST BY TREATMENT WITH HUMAN INTERFERON

We investigated the depression induced by human interferons using the forced swimming test in mice. Intravenous (i.v.) administration of int erferon-alpha s (natural interferon-alpha, recombinant interferon-alph a-2a and recombinant interferon-alpha-2b, 600-60 000 IU/kg) increased the immobility time in the forced swimming test in a dose-dependent ma nner, but natural interferon-beta and recombinant interferon-gamma-1a did not affect the immobility time. The increase in the immobility tim e induced by recombinant interferon-alpha-2b peaked at 15 min after do sing. Administration of recombinant interferon-alpha-2b (6000 IU/kg, i .v.) once daily for 7 consecutive days increased the immobility time, but natural interferon-beta and recombinant interferon-gamma-1a did no t. Recombinant interferon-alpha-2b in combination with the anti-depres sants imipramine (10 mg/kg, i.p.) and mianserin (20 mg/kg, i.p.) did n ot increase the immobility time. These results suggest that interferon -alpha has a greater potential for inducing depression than interferon -beta and -gamma, and that anti-depressants are effective against inte rferon-alpha-induced depression. (C) 1998 Elsevier Science B.V. All ri ghts reserved.