Possible involvement of ATP-sensitive potassium channels in the antidepressant-like effect of baclofen in mouse forced swimming test.

BACKGROUND

Previous study confirmed that the acute treatment with baclofen by inhibition of the l-arginine-nitric oxide (NO) pathway diminished the immobility behavior in the forced swimming test (FST) of mice. Considering the involvement of NO in adenosine triphosphate (ATP)-sensitive potassium channels (K), in the present study we investigated the involvement of K channels in antidepressant-like effect of baclofen in the forced swimming test (FST).

METHODS

After assessment of locomotor behavior in the open-field test (OFT), FST was applied for evaluation of the antidepressant-like activity of baclofen in mice. Baclofen at different doses (0.1, 0.3, and 1mg/kg) and fluoxetine (20mg/kg) were administrated by intraperitoneal (ip) route, 30min before the FST or OFT. To clarify the probable involvement of K channels, after determination of sub-effective doses of glibenclamide as a K channel blocker and cromakalim, as an opener of these channels, they were co-administrated with the sub-effective and effective doses of baclofen, respectively.

RESULTS

Baclofen at dose 1mg/kg significantly decreased the immobility behavior of mice similar to fluoxetine (20mg/kg). Co-administration of gelibenclamide sub-effective dose (1mg/kg) with baclofen (0.1mg/kg) showed a synergistic antidepressant-like effect in the FST. Also, sub-effective dose of cromakalim (0.1mg/kg) inhibited the antidepressant-like effect of baclofen (1mg/kg) in the FST. All aforementioned treatments had not any impact on the locomotor movement of mice in OFT.

CONCLUSIONS

Our study for the first time revealed that antidepressant-like effect of baclofen on mice is K-dependent, and baclofen seems that exert this effect by blocking the K channels.