6-OHDA-LESIONS OF THE NUCLEUS-ACCUMBENS DISRUPT THE ACQUISITION BUT NOT THE MAINTENANCE OF ETHANOL-CONSUMPTION IN THE ALCOHOL-PREFERRING P LINE OF RATS

The aim of the present study was to determine whether reduction of dop amine (DA) innervation to the nucleus accumbens (ACB) alters the maint enance and/or acquisition of ethanol drinking in female alcohol-prefer ring P rats. Compared with sham-lesioned animals, bilateral microinjec tions of 6-OHDA (12 mu g/2.4 mu l/site) into the ACB did not alter the consumption of 10% ethanol in rats that had prior experience of ethan ol drinking, with both sham- and 6-OHDA-lesioned groups recovering to presurgical consumption levels at similar rates. On the other hand, th e identical lesion procedure disrupted the acquisition of ethanol inta ke in rats with no ethanol-drinking experience prior to the lesions. A sham-lesioned group attained an ethanol intake of approximately 7 g/k g/day in 1 week, which was maintained over the following 2-week period , while the ethanol intake of the 6-OHDA-lesioned group was approximat ely 60% lower after 1 week and 30% lower at the end of 3 weeks. DA con tent of the ACB was 60% lower in both groups of the 6-OHDA-treated rat s compared with the controls. The results suggest that different neura l mechanisms may underlie the acquisition and maintenance of ethanol d rinking behavior; the ACB DA system appears to play an important role in the acquisition of ethanol drinking.