Effects of chronic alcohol ingestion on the mesostriatal dopamine system in the rat

The effects of chronic alcohol use on the mesostriatal dopamine (DA) system remain relatively unknown. The aim of the present study was to assess mult iple measures of the status of the mesostriatal DA system in rats chronical ly fed an alcohol diet for approximately 1 year. Tissue levels of DA and it s metabolite, 3,4-dihydroxyphenylacetic acid, were significantly decreased in both the dorsal striatum (34 and 33%, respectively) and ventral striatum (33 and 36%, respectively) in alcohol-fed rats compared to pair-fed matche d controls. Western blotting revealed a mean 20% decrease in tyrosine hydro xylase protein levels in the dorsal and ventral striatum of alcohol-fed ani mals while dopamine transporter protein levels from the same animals were s ignificantly increased compared to controls (mean 60% increase for the dors al and ventral striatum). The present results demonstrate significant alter ations in the mesostriatal DA system after 1 year of chronic alcohol use. I t is possible that the observed changes in DA synthesis and re-uptake measu res result in altered intracellular and extracellular DA levels, perhaps co ntributing to the addictive properties of alcohol. (C) 2001 Elsevier Scienc e Ireland Ltd. All rights reserved.