Nucleus accumbens opioid, GABaergic, and dopaminergic modulation of palatable food motivation: contrasting effects revealed by a progressive ratio study in the rat

Behav Neurosci. 2003 Apr;117(2):202-11. doi: 10.1037/0735-7044.117.2.202.


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.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Analgesics, Opioid / pharmacology
  • Animals
  • Carbohydrates
  • Dextroamphetamine / pharmacology
  • Dopamine / physiology*
  • Dopamine Uptake Inhibitors / pharmacology
  • Dose-Response Relationship, Drug
  • Enkephalin, Ala(2)-MePhe(4)-Gly(5)- / pharmacology
  • Feeding Behavior / drug effects
  • Feeding Behavior / physiology*
  • GABA Agonists / pharmacology
  • Male
  • Motivation
  • Muscimol / pharmacology
  • Narcotics / metabolism*
  • Nucleus Accumbens / drug effects
  • Nucleus Accumbens / physiology*
  • Rats
  • Rats, Sprague-Dawley
  • Reinforcement Schedule
  • Time Factors
  • gamma-Aminobutyric Acid / physiology*


  • Analgesics, Opioid
  • Carbohydrates
  • Dopamine Uptake Inhibitors
  • GABA Agonists
  • Narcotics
  • Enkephalin, Ala(2)-MePhe(4)-Gly(5)-
  • Muscimol
  • gamma-Aminobutyric Acid
  • Dextroamphetamine
  • Dopamine