The effects of a L-type calcium channel blocker, ethaverine were investigated in the
rat forced swimming test, after single and repeated administration. Ethaverine in
doses of 20 mg/kg, 40 mg/kg after single and repeated administration reduced
significantly the duration of immobility in the forced swimming test. Fluoxetine
administered in a single dose of 40 mg/kg did not influence the duration of
immobility, but fluoxetine in a dose of 40 mg/kg administered repeatedly reduced
significantly the duration of immobility. Ethaverine in a dose of 10 mg/kg did not
affect the immobility after single and repeated administration. Imipramine and
fluoxetine in doses which were not effective by themselves, increased the
immobilityreducing effect when administered concormitantly with ethaverine in a dose
of 10 mg/kg. Imipramine in a dose of 20 mg/kg and fluoxetine in a dose of 80 mg/kg,
administered alone reduced the immobility time. The reduction of immobility after the
concormitant administration of ethaverine in a dose of 10 mg/kg and imipramine in a
dose of 20 mg/kg, fluoxetine in a dose of 80 mg/kg was significantly greater than
after imipramine or fluoxetine, administered alone. The anti-immobility effect of the
ethaverine was significantly counteracted by haloperidol in a dose of 0.5 mg/kg. The
effects of ethaverine on the levels of monoamines and their metabolites were also
investigated in rat striatum, cerebral cortex, cerebellum, medulla oblongata,
hypothalamus, midbrain, hippocampus. Treatment with ethaverine caused alterations on
the levels of dopamine and its metabolite in rat striatum, cerebral cortex,
hypothalamus, medulla oblongata, cerebellum, but not on the levels of norepinephrine
and serotonin and its metabolite. The observed effects of ethaverine indicate that
ethaverine may have an antidepressant activity and may interact with the brain
dopaminergic system. The present results suggest that the concormitant administration
of ethaverine and antidepressants may have a more potent therapeutic antidepressant
effect and/or may permit reduction of the dose of antidepressant and thus diminish its
side effects.
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