Chunk #33 — 3 Neural Substrates for the Negative Emotional State Associated with Alcoholism — 3.1 Within-System Neuroadaptations that Contribute to the Compulsivity Associated with the Dark Side of Alcoholism
the release of these transmitters over the 8 h withdrawal period. Self-administration of ethanol reinstated and maintained dopamine release at pre-withdrawal levels but failed to completely restore serotonin efflux. These findings suggested that deficits in nucleus accumbens monoamine release may contribute to the negative affective consequences of ethanol withdrawal and thereby motivate ethanol-seeking behavior in dependent subjects (Weiss et al. 1996). Similar dramatic decreases in extracellular dopamine in the nucleus accumbens, measured by microdialysis, were found in a study in which animals were tested for 8 h into ethanol withdrawal produced by chronic repeated ethanol injections of up to 5 g/kg every 6 h for six consecutive days using the Majchrowicz procedure (Majchrowicz 1975; Rossetti et al. 1999). Thus, as a result, ethanol-dependent animals may show a much greater percentage increase in dopamine release in the nucleus accumbens during ethanol self-administration during withdrawal because baseline levels of dopamine are so low during withdrawal (Weiss et al. 1996).
