Effects of aripiprazole, an atypical antipsychotic, on the motor alterations induced by acute ethanol administration in mice.

Aripiprazole is an antipsychotic that acts as a partial agonist at dopamine receptors. As the effects of most drugs of abuse converge to enhance dopamine-mediated neurotransmission, the present study was designed to test the hypothesis that aripiprazole would inhibit the acute effects of ethanol, a widely abused substance. Male Swiss mice received acute injections and were evaluated for motor activity in three distinct tests. In the open field, ethanol (1.5, 2.5 and 3.5 g/kg) induced an increase in locomotion in a U-shaped dose-related fashion, whereas aripiprazole (0.1, 1 and 10 mg/kg) did not affect this parameter. All the doses of the antipsychotic were able to prevent the stimulant effects of 2.5 g/kg of ethanol. In the rotarod test, ethanol (2.5 and 3.5 g/kg) reduced the latency to fall from the apparatus, an effect also observed with the higher dose of aripiprazole. Contrary to what was observed in the open field, this antipsychotic did not interfere with the effects of ethanol in motor balance. Finally, we tested animals in the wire hang test, in which ethanol, but not aripiprazole, reduced latency to fall at all doses. In this test, aripiprazole did not change ethanol effects. The present data lead to the conclusion that aripiprazole prevents the stimulant effects of ethanol on locomotion, without interfering with the motor impairment induced by this drug.