In vivo electrochemical determination of extracellular dopamine in the caudate of freely-moving rats after a low dose of ethanol.

Low doses of ethanol (i.e. less than 1 g/kg) elicit behavioral stimulation, control discriminative performance and mediate reinforcement in rats. These effects are thought to be mediated through central dopaminergic neuronal systems. In the present study, dopamine and serotonin/uric acid release from caudate was measured by in vivo voltammetry in freely-moving, unanesthetized rats after administration of a low dose of ethanol (600 mg/kg, IP). Within 15 min after a single ethanol administration, extracellular dopamine levels significantly increased in caudate, peaking at 35 min, and returning to baseline by 75 min. In addition, ethanol caused an attenuation of a second voltammetric signal that correlates with extracellular serotonin/uric acid concentrations, and this effect persisted through the course of the experiments. These neurochemical changes may underlie behavioral responses found after low doses of ethanol.