Ascorbic acid antagonizes ethanol-induced locomotor activity in the open-field

It has been reported that ascorbic acid (AA) antagonizes the physiological and behavioral effects of dopamine (DA). AA reduces locomotor activity indu ced by dopaminergic agonist drugs. Also, AA amplifies the action of antidop aminergic drugs. Ethanol, like other drugs, produces a release of DA in the mesolimbic pathway, and at some doses, induces locomotor activity in mice. The ethanol-induced locomotor activity could be dopamine-dependent because it can be reduced by antidopaminergic drugs. In the present study, we inve stigated whether an acute administration of AA reduces ethanol-induced loco motor behavior. AA, at doses (0.0, 21.85, 87.5, 175, 350, and 1400 mg/kg) w as injected IP into mice, 0, 30, 60, or 90 min before an IP injection of et hanol (0.0, 0.8, 1.6, 2.4, and 3.2 g/kg). Locomotor activity was evaluated in open-field chambers. Our results showed that AA (350 and 1400 mg/kg) red uced ethanol-induced locomotor activity when injected 30 min before ethanol treatment. This effect was lost when ethanol was administered 90 min after AA injection. AA also reduced locomotor activity produced by d-amphetamine and methanol. The results support a pro-dopaminergic action of ethanol, an d suggest a common dopaminergic pathway for the drugs of abuse in locomotor activity. (C) 1999 Elsevier Science Inc.