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 |
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Authors: | Satoshi Ikemoto William J McBride James M Murphy Larry Lumeng Ting-Kai Li |
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Institution: | Institute of Psychiatric Research, Department of Psychiatry (S.I., W.J.M., J.M.M.) and the Departments of Medicine and Biochemistry, Indiana University School of Medicine (L.L., T-K.L.);the Department of Psychology, Purdue School of Science, IUPUI (J.M.M.);and Veterans Administration Hospital (L.L.), Indianapolis, Indiana. |
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Abstract: | The aim of the present study was to determine whether reduction of dopamine (DA) innervation to the nucleus accumbens (ACB) alters the maintenance and/or acquisition of ethanol drinking in female alcohol-preferring P rats. Compared with sham-lesioned animals, bilateral microinjections of 6-OHDA (12 μg/2.4 μl/site) into the ACB did not alter the consumption of 10% ethanol in rats that had prior experience of ethanol drinking, with both sham- and 6-OHDA-lesioned groups recovering to presurgical consumption levels at similar rates. On the other hand, the identical lesion procedure disrupted the acquisition of ethanol intake in rats with no ethanol-drinking experience prior to the lesions. A sham-lesioned group attained an ethanol intake of approximately 7 g/kg/day in 1 week, which was maintained over the following 2-week period, while the ethanol intake of the 6-OHDA-lesioned group was approximately 60% lower after 1 week and 30% lower at the end of 3 weeks. DA content of the ACB was 60% lower in both groups of the 6-OHDA-treated rats compared with the controls. The results suggest that different neural mechanisms may underlie the acquisition and maintenance of ethanol drinking behavior; the ACB DA system appears to play an important role in the acquisition of ethanol drinking. |
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Keywords: | Alcohol Self-Administration 6-Hydroxydopamine Lesions Nucleus Accumbens Alcohol-Preferring P Rats |
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