Intra-lateral septal infusions of folic acid alone or combined with various antidepressant drugs produce antidepressant-like actions in male Wistar rats forced to swim

Intra-cerebral administrations of folic acid produce antidepressant-like effects; either alone or combined with several antidepressant drugs. However, the specific limbic structures implied in the antidepressant-like actions of folic acid are un-known. Thus, intra-lateral septal infusions of folic acid (5.0 nmol, P < 0.05; 10.0 nmol, P < 0.05) or oral administrations of folic acid (50 mg/kg, P < 0.05, p.o.; 75.0; mg/kg, P < 0.05, p.o.) or systemic administrations of fluoxetine (20.0 mg/kg, P < 0.05; 25.0 mg/kg, P < 0.05) reduced immobility by increasing swimming behavior in the forced swimming test (FST) of male Wistar rats. Conversely, desipramine (10.0 mg/kg, P < 0.05; 15.0 mg/kg, P < 0.05) reduced immobility by increasing climbing behavior. Subthreshold doses of folic acid (2.5 nmol/intra-LSN) combined with subthreshold doses of folic acid (25.0 mg/kg, p.o., P < 0.05) or with subthreshold doses of fluoxetine (15.0 mg/kg, P < 0.05) and they produced antidepressant-like effects which were canceled by ketanserin. In conclusion, intra-lateral septal infusions of folic acid alone or combined with systemic doses of folic acid or fluoxetine reduced immobility in the FST. These antidepressant-like actions, probably, were due to modifications of the serotonergic system since swimming behavior was increased and these effects were canceled by ketanserin.