Terminal effects of ethanol on dopamine dynamics in rat nucleus accumbens: an in vitro voltammetric study.

To assess the direct effects of acute ethanol on dopamine (DA) terminals, evoked DA release and uptake were measured in rat nucleus accumbens slices using fast-scan cyclic voltammetry. Low and moderate concentrations of ethanol (20, 45 and 100 mM) did not alter evoked DA release, while high concentrations (150 and 200 mM) significantly decreased DA release (18 and 36%, respectively) in a calcium-dependent manner. No significant difference was found between the rate of DA disappearance measured before and after the drug. These data indicate that uptake of DA through the dopamine transporter is unaffected by ethanol, even at high concentrations. Therefore, low to moderate concentrations of ethanol have no effect on DA dynamics at the level of the nerve terminal in the nucleus accumbens. This is consistent with the hypothesis that cell body regions of DA neurons are the primary target for the stimulating and reinforcing effects of ethanol. High concentrations of ethanol can locally depress DA release, and this may correlate with the sedative actions of the drug. Copyright 2001 Wiley-Liss, Inc.