Evaluation of the pharmacological involvement of ATP-sensitive potassium (K) channels in the antidepressant-like effects of topiramate on mice.

Acute doses of topiramate (TPM) have been shown to reduce immobility time in the mice forced swimming test (FST) through inhibition of the nitric oxide (NO) pathway. Adenosine triphosphate-sensitive potassium (K) channels are known to have an active role in depression. This study investigates the potential participation of K channels in the antidepressant-like effect of TPM through the stimulatory effects of NO. FST and tail suspension tests (TST) were applied to adult male mice for assessment of the antidepressant-like activity of TPM. Different doses of glibenclamide and cromakalim were also applied in order to investigate the involvement of K channels. Fluoxetine was used as a positive control for evaluation of antidepressant-like effects. In addition, each animal's locomotor activity was evaluated by the open-field test (OFT). TPM (30 mg/kg intraperitoneal (i.p.)) had a significant reductive effect on the immobility behavior similar to fluoxetine (20 mg/kg). Co-administration of sub-effective doses of glibenclamide (1 mg/kg i.p.) and TPM (10 mg/kg i.p.) led to significant synergistic effects in FST and TST. Additionally, the results showed that administration of the sub-effective dose of cromakalim (0.1 and 0.3 mg/kg i.p.) blocked the antidepressant-like effects of TPM (30 mg/kg i.p.) in both tests. These interventions had no impact on the locomotor movement of mice in OFT. This study shows that the antidepressant-like activity of TPM may potentially be mediated by the blocking of the K channels.