Anxiolytic effects of swimming exercise and ethanol in two behavioral models: beneficial effects and increased sensitivity in mice
Several behavioral mechanisms have been suggested to explain the effects of ethanol or physical exercise on anxiety. The purpose of the current study was to assess the effects of chronic and acute administration of ethanol on swimming exercise in mice, sequentially submitted to the elevated plus-maze and open-field tests. In the first experiment, sedentary or physical exercise groups received chronic treatment with ethanol (0.1, 0.2, 0.4, 2 or 4 g ethanol/kg/day by oral gavage) for 14 days before the tests. In the second experiment, groups received a single dose of ethanol (ip: 0.6, 0.8, 1.0 or 1.2 g/kg), ten minutes before the start of behavioral tests. The present study found an anxiolytic-like effect after chronic ethanol treatment or swimming exercise, evidence of beneficial effects. Moreover, we conclude that exercise can increase behavioral sensitivity to ethanol in acute treatment. The experiments described here show that the effects of ethanol on the behavior displayed in the elevated plus-maze and open-field are not only dose-dependent but also modified by swimming exercise. These results may provide valuable insights into possible molecular mechanisms governing these adaptations.