Interaction of RO 15-4513 and ethanol on the behaviour of mice: antagonistic or additive effects?

Opposite effects were observed of ethanol on the behaviour of mice in the two chambered light/dark test. At a low dose, it had anxiogenic effects, while it produced anxiolytic effects at a higher dose. Selective antagonistic actions of RO 15-4513 against the behavioural effects of ethanol have been reported by others without intrinsic actions. In contrast, we found intrinsic depressive properties of RO 15-4513. This drug reduced locomotion in a running wheel test. We suggest that RO 15-4513 reversed certain effects of ethanol in an additive, rather than interactive, manner. In addition, RO 15-4513 did not block the sedation produced by a high dose of ethanol. Since RO 15-4513 revealed proconvulsant properties, it is proposed that the depressive effects of this drug could be related to its proconvulsive activity.