Fructose-conditioned flavor-flavor preferences in the rat: Dopaminergic and opioid substrates in the nucleus accumbens and amygdala
Item
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Title
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Fructose-conditioned flavor-flavor preferences in the rat: Dopaminergic and opioid substrates in the nucleus accumbens and amygdala
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Identifier
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d_2009_2013:c30b945bea7d:10540
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identifier
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10917
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Creator
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Bernal, Sonia Y.,
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Contributor
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Richard J. Bodnar
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Date
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2010
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Language
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English
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Publisher
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City University of New York.
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Subject
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Psychology
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Abstract
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Systemic dopamine (DA) D1 (SCH23390) and D2 (raclopride) receptor antagonists reduce acquisition and expression of fructose-conditioned flavor preferences (CFP) in rats. Given DA involvement in nucleus accumbens shell (NAcS) and amygdala (AMY) in learning of food reward, the first and second aims examined whether NAcS or AMY D1 or D2 antagonism altered acquisition and expression of fructose-CFP. In expression, food-restricted rats with bilateral NAcS or AMY cannulae were trained to drink a flavored fructose (8%) and saccharin (0.2%) solution or another flavored 0.2% saccharin solution. Two-bottle tests with both flavors in saccharin solutions occurred 10 min following NAcS or AMY doses of 0, 12, 24 or 48 nmol of SCH23390 or raclopride. CFP expression following vehicle (76-77%) was significantly reduced by SCH23390 (48 nmol: NAcS, 62%; AMY, 66%) and raclopride (NAcS: 24 nmol, 63%; 48 nmol, 68%). In acquisition, rats received 12 nmol of SCH23390 (D1) or raclopride (D2) in the NAcS or AMY 10 min prior to one-bottle training sessions. Yoked controls received vehicle with limited CS intakes, whereas untreated controls were not injected or limited. Two-bottle tests revealed initial CFP in all groups that remained stable in untreated and yoked controls, but were lost over six test sessions in the AMY D1 and NAcS D1 and D2 groups. Thus, D1 and D2 receptor blockade in the NAcS and AMY significantly attenuated expression, but not initial acquisition of fructose-CFP, and hastened extinction of fructose-CFP.;Systemic naltrexone (NTX), an opioid receptor antagonist, suppressed sweet intake, but failed to affect acquisition or expression of fructose-CFP. Because opioids in the NAc and AMY are implicated in food reward, the third and fourth aims examined whether NTX in these sites altered expression of fructose-CFP. Food-restricted rats with bilateral NAc or AMY cannulae were trained and tested in identical protocols using NTX doses of 0, 1, 25 or 50 ug. Significant CFP was observed following all NTX doses in all sites. Thus, DA, but not opioids modulate flavor-flavor conditioning through a regionally-distributed limbic brain network.
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Type
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dissertation
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Source
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2009_2013.csv
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degree
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Ph.D.
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Program
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Psychology
