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. Whereas 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.
