Jpn. J. Pharmacol. 85 (3), 327-330 (2001)

Comparison of Noradrenergic and Serotonergic Antidepressants in Reducing Immobility Time in the Tail Suspension Test

Jun Fujishiro1,2,*, Taiichiro Imanishi2, Jun Baba2 and Kenji Kosaka1

1Department of Psychiatry, Yokohama City University School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
2Pharmaceutical Research Center, Meiji Seika Kaisha, Ltd., 760 Morooka-cho, Kohoku-ku, Yokohama 222-8567, Japan
*Corresponding author (affiliation #2). FAX: +81-45-545-3152

Abstract: We examined the effects of two noradrenergic tricyclic antidepressants and two selective serotonin re-uptake inhibitors in the tail suspension test, with a suspension period of 30 min instead of the usual 10 min. Within the first 10 min, desipramine, nortriptyline and fluvoxamine significantly reduced the duration of immobility. ‚vhereas desipramine and nortriptyline were also efficacious in the rest of the test period, fluvoxamine was not. Fluoxetine showed no significant effect throughout the study period. These results suggest that a prolonged tail suspension test results in functional changes in the noradrenergic and serotonergic systems and alters the sensitivity to antidepressants.

Keywords: Tail suspension test, Antidepressant, Immobility time

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