[Effect of selective serotonin reuptake inhibitor fluoxetine on symptoms of depression-like behavior in WAG/Rij rats].

A possibility to correct behavioral symptoms of depression-like behasior in WAG/Rij rats with selective serotonin reuptake inhibitor antidepressant drug fluoxetine was studied. The efficacy of fluoxetine was compared with that of tricyclic antidepressant imipramine. Vehicle-treated WAG/Rij rats compared with the corresponding group of Wistar rats exhibited symptoms of depression-like behavior: a decreased level of exploratory activity and grooming reactions in the open field test, increased immobility in the forced swimming test, and decreased sucrose intake and preference (anhedonia). Differences in anxiety level in the light-dark choice test between WAG/Rij and Wistar rats were not found. Chronic injection of fluoxetine (5 mg/kg, i.p., for 15 days) didn't exert substantial influence on the anxiety level in the light-dark choice test both in WAG/Rij and Wistar rats. In the open field test, fluoxetine didn't significantly affect behavior of "depressive" WAG/Rij rats but induced anxiogenic effect in "normal" Wistar rats (a decrease in the number of center entries and an increase in the number of grooming reactions). In the forced swimming test, fluoxetine induced antidepressant effect (a decrease in immobility time and increase in the time of swimming) statistically significant in Wistar rats and at the level of tendency in WAG/Rij rats. In the sucrose consumption test, fluoxetine enhanced sucrose intake in "depressive" WAG/Rij rats and induced a tendency to a decrease in sucrose intake in "normal" Wistar rats. Fluoxetine didn't change sucrose preference (%) both in WAG/Rij and Wistar rats. In "depressive" WAG/Rij rats, selective serotonin reuptake inhibitor antidepressant fluoxetine was less effective than tricyclic antidepressant imipramine. However, a therapeutic effect of imipramine was apparent only after the cessation of chronic treatment. During treatment, worsening ofbehavioral characteristics was seen not only in "normal" Wistar rats but to an even greater degree in "depressive" WAG/Rij rats. Fluoxetine caused worsening of some behavioral characteristics only in "normal" Wistar rats. In "depressive" WAG/Rij rats, the therapeutic effect offluoxetine developed earlier than that of imipramine and was not accompanied by an adverse side effect on behavior of animals.