Effects of acute administration of bupropion on behavior in the elevated plus-maze test by NMRI mice.

Bupropion attenuates some symptoms of nicotine abstinence, although its effects on anxiety are unclear. The present study investigates acute effects of bupropion (5, 10, 20 and 40 mg/kg) on anxiety as expressed in the elevated plus-maze test in male NMRI mice. Given the influence of locomotion in this test, effects of bupropion were also evaluated in an actimeter. Spontaneous motor activity remained significantly increased in mice treated with 10, 20 and 40 mg/kg of bupropion during the 60 min recorded. Results from the elevated plus-maze showed that 20 mg/kg increased total arm entries and 40 mg/kg increased total and open arm entries. Although the increase in the number of visits to the open arms suggests an anxiolytic-like effect, if the actions of this drug on locomotion are taking into account, one may conclude that the increase in open arm entries observed with the highest doses is a motor effect rather than anxiolysis per se. In addition, ethological measures failed to detect a clear anxiolytic profile since neither a significant decrease in total stretched attend postures nor a reduction in the percentage of protected forms of head dipping or stretched attend postures were observed at any dose tested. These results suggest that the elevated plus-maze is sensitive to the motor actions of bupropion and that this should be taken into account in the evaluation of the "emotional" effects of this drug.