Ethanol-Induced Taurine Elevation in the Rat Dorsal Striatum

In the search for the primary mechanism underlying the dopamine elevating properties of ethanol we have established that raised levels of taurine in the nucleus accumbens (nAc) is pivotal. In the nAc, the release of taurine appears to be connected to osmoregulation, and neither taurine nor dopamine is increased if ethanol is administered in a hypertonic saline solution. However, even though the nAc is important for drug-reinforcement, manifestation of addiction has been postulated to recruit the more dorsal parts of the striatum (DS). How ethanol influences dopamine and taurine in the DS and their role in addiction is thus far poorly understood. By means of in vivo microdialysis in freely moving rats we concomitantly monitored extracellular levels of dopamine and taurine in the DS following administration of ethanol diluted either in an isotonic or hypertonic saline solution. In a different set of rats, placed in a voluntary ethanol consumption paradigm (intermittent access to 20% ethanol for 2 months), taurine and dopamine were monitored following an acute injection of ethanol. We found that neither administration of ethanol diluted in a hypertonic saline solution, nor 2 months of moderate ethanol consumption, influence the ethanol-induced increase of taurine in the DS. We propose that there may be regional differences in the relationship between taurine, dopamine and ethanol in the nAc and in the DS. It remains to be determined if this subregion-specificity is important for the transition from recreational drug use to a compulsive habit.