title: Nucleus accumbens opioid, GABaergic, and dopaminergic modulation of palatable food motivation: contrasting effects revealed by a progressive ratio study in the rat.
abstract: The current studies were designed to evaluate whether incentive motivation for palatable food is altered after manipulations of opioid, GABAergic, and dopaminergic transmission within the nucleus accumbens. A progressive ratio schedule was used to measure lever-pressing for sugar pellets after microinfusion of drugs into the nucleus accumbens in non-food-deprived rats. The mu opioid agonist D-Ala2, NMe-Phe4, Glyo15-enkephalin and the indirect dopamine agonist amphetamine induced a marked increase in break point and correct lever-presses; the GABA(A) agonist muscimol did not affect breakpoint or lever-presses. The data suggest that opioid, dopaminergic, and GABAergic systems within the accumbens differentially modulate food-seeking behavior through mechanisms related to hedonic evaluation of food, incentive salience, and control of motor feeding circuits, respectively.
authors.affiliation: Department of Psychiatry, University of Wisconsin-Madison Medical School, 53715, USA.
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.forename: Christian
authors.initials: C
authors.lastname: Balmadrid
authors.forename: Ann E
authors.initials: AE
authors.lastname: Kelley
mesh_terms: D000701:Analgesics, Opioid / Q000494:pharmacology; D000818:Animals; D002241:Carbohydrates; D003913:Dextroamphetamine / Q000494:pharmacology; D004298:Dopamine / Q000502:physiology*; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)- / Q000494:pharmacology; D005247:Feeding Behavior / Q000187:drug effects / Q000502:physiology*; D018755:GABA Agonists / Q000494:pharmacology; D008297:Male; D009042:Motivation; D009118:Muscimol / Q000494:pharmacology; D009294:Narcotics / Q000378:metabolism*; D009714:Nucleus Accumbens / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012055:Reinforcement Schedule; D013997:Time Factors; D005680:gamma-Aminobutyric Acid / Q000502:physiology*
chemical_list: D000701:Analgesics, Opioid; D002241:Carbohydrates; D018765:Dopamine Uptake Inhibitors; D018755:GABA Agonists; D009294:Narcotics; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D009118:Muscimol; D005680:gamma-Aminobutyric Acid; D003913:Dextroamphetamine; D004298:Dopamine