Hydroalcoholic Extract of Avena sativa Exerts Antidepressant-like Effects Through the Monoaminergic System

Previous research has demonstrated the antidepressant potential of Avena sativa; however; its mode of action is still unknown. Hence, the role of the monoaminergic system in the antidepressant-like activity of A. sativa was investigated by using the tail suspension test in the present study. The mice intraperitoneally (i.p.) received the hydroalcoholic extract of A. sativa (50, 100, and 200 mg/kg) 30 min before the tail suspension test. The participation of the monoaminergic system in the antidepressant-like activity of A. sativa (200mg/kg) was assessed by administration of several receptor antagonists, 60 min before the administration of the extract in the test. Moreover, the effect of A. sativa on animals’ locomotion was examined by using open-field test. All doses of the A. sativa extract caused a significant antidepressant-like effect (p<0.001) in the tail suspension test, without any significant change in the mice locomotion in the open-field test (p>0.05). In addition, pre-treatment of the animals with sulpiride, haloperidol, SCH23390, p-chlorophenylalanine, ketanserin, WAY100135, reserpine, yohimbine, and prazosin abolished the antidepressant-like activity of A. sativa. Furthermore, the joint administration of sub-effective doses of A. sativa with fluoxetine and imipramine produced a synergistic antidepressant-like effect. Avena sativa induced an antidepressant-like effect in tail suspension test that is dependent on the monoaminergic system; however; clinical studies are required for showing the beneficial effects of the extract in humans.