ABSTRACT
Objective To establish chronic stress model of depression in adolescent rats and to examine the effects of different antidepressant treatment on depression and anxiety-related behaviors.Methods Male Wistar rats were given 21-day chronic mild stress (CMS) during their adolescence (postnatal day 30～50, PND30～50).During stress period, rats were treated with fluoxetine (10 mg/kg i.p.) or imipramine (10 mg/kg i.p.), respectively.After stress, rats were tested for behavioral observation using body weight gain, saccharine test, open field and elevated plus-maze (EPM).Results Compared with control/vehicle (n=10) group, stress/vehicle (n=11) group displayed lower weight gain, saccharine preference index and the number of rearing in open field (P<0.05).Antidepressant fluoxetine, but not imipramine reversed anhedonia and the decrease of the number of rearing induced by stress.In addition, compared with early adolescent(PND29) rats, late adolescent (PND52) rats in control/vehicle group exhibited less open arm entries and open arm time, more closed arm time in EPM (P<0.05).Rats in stress/vehicle group showed more open arm entries and less closed arm time than controls(P<0.05).Both fluoxetine and imipramine had no effects on such changes.Conclusions Stress can induce the depression-like behavior in adolescent rats.Fluoxetine, but not imipramine,can effectively reverse anhedonia induced by stress.However, Both antidepressants have no significant effects on stress-induced decrease in developmental increment of anxious behavior during adolescence.These data suggest that chronic mild stress have complicated effects on depressive and anxious behavior in adolescent rats.