Acute administration of 3-nitropropionic acid, a reactive oxygen species generator, boosts ethanol-induced locomotor stimulation. New support for the role of brain catalase in the behavioural effects of ethanol

The antioxidant enzyme catalase by reacting with H2O2, forms the compound known as compound I (catalase-H2O2). This compound is able to oxidise ethanol to acetaldehyde in the CNS. It has been demonstrated that 3-nitropropionic acid (3-NPA) induces the activity of the brain catalase-H2O2 system. In this study, we tested the effect of 3-NPA on both the brain catalase-H2O2 system and on the acute locomotor effect of ethanol. To find the optimal interval for the 3-NPA–ethanol interaction mice were treated with 3-NPA 0, 45, 90 and 135 min before an ethanol injection (2.4 mg/kg). In a second study, 3-NPA (0, 15, 30 or 45 mg/kg) was administered SC to animals 90 min before saline or several doses of ethanol (1.6 or 2.4 g/kg), and the open-field behaviour was registered. The specificity of the effect of 3-NPA (45 mg/kg) was evaluated on caffeine (10 mg/kg IP) and cocaine (4 mg/kg)-induced locomotion. The prevention of 3-NPA effects on both ethanol-induced locomotion and brain catalase activity by l-carnitine, a potent antioxidant, was also studied. Nitropropionic acid boosted ethanol-induced locomotion and brain catalase activity after 90 min. The effect of 3-NPA was prevented by l-carnitine administration. These results indicate that 3-NPA enhanced ethanol-induced locomotion by increasing the activity of the brain catalase system.