The antidepressant-like effects of topiramate alone or combined with 17β-estradiol in ovariectomized Wistar rats submitted to the forced swimming test.

Rationale: There is a significant delay in the clinical response of antidepressant drugs, and antidepressant treatments produce side effects.

Objective: We examined the relationship between 17β-estradiol and topiramate in ovariectomized Wistar rats submitted to the forced swimming test (FST).

Methods: Topiramate was administered alone or combined with 17β-estradiol to ovariectomized rats submitted to the FST.

Results: Topiramate (20 mg/kg, P < 0.05; 30 mg/kg, P < 0.05) reduced immobility by increasing swimming; these effects were antagonized by finasteride (50 mg/kg). In interaction experiments, topiramate (10 mg/kg) plus 17β-estradiol (5 micrograms per rat; P < 0.05) reduced immobility by increasing swimming behavior. Besides, 17β-estradiol (2.5 micrograms per rat) shortened the onset of the antidepressant-like effects of topiramate (P < 0.05). In the open field test, topiramate alone or combined with 17β-estradiol (P < 0.05) reduced locomotion.

Conclusions: Topiramate alone or combined with 17β-estradiol produced antidepressant-like actions; and 17β-estradiol shortened the onset of the antidepressant-like effects of topiramate.