[Abstract Title]. - Society for Neuroscience

predator) have been shown previously to reduce feeding and increase defensive behaviors in the
rat. The mu-opioid peptide agonist DAMGO (D-Ala2, NMe-Phe4, Glyol5-enkephalin) was
chronically microinfused directly into the Acb core of male Sprague-Dawley rats. Separate
groups of animals received 4 daily microinfusions of either DAMGO or saline into the Acb core
10 minutes before being placed in a test chamber with 5 grams of sweetened fat. After
completion of these four chronic treatment days, all rats received a sham injection and were
allowed to eat sweetened-fat ad-libitum. Enhancement of baseline fat intake was not observed in
DAMGO-pretreated rats. Two days later, sham-injected animals were exposed to the ferret
predator for 5 minutes and given the opportunity to eat sweetened-fat. Control rats showed a
marked decrease in ad-libitum sweetened-fat intake immediately after ferret exposure whereas
the prior chronic κ-opioid receptor stimulation by DAMGO prevented this stress-induced
anorexic effect. Ad-libitum fat intake returned to pre-ferret baseline levels in all rats on a
subsequent test day. Hence, chronic intra-Acb DAMGO pretreatment fundamentally alters the
behavioral response to predator stress. These results establish a role for the nucleus accumbens in
regulating stress-induced anorexia and may imply that individual differences in the effects of
stress on palatable food intake may relate to nucleus accumbens opioid tone.
Disclosures: L. Pascal , None; V.P. Bakshi, None; B.A. Baldo, None; R.C. Spencer,
None; A.E. Kelley, None.
Poster
298. Neural Mechanisms of Reward: Self-Administration and Opioid Modulation
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 298.12/TT45
Topic: F.03.d. Reward
Support: NIMH Grant MH63649
Title: Hyperdopaminergic mice exhibit enhanced 'wanting' but normal modulation of 'liking'
Authors: *G. M. SPROW 1 , S. V. MAHLER 1 , K. C. BERRIDGE 1 , J. A. BEELER 2 , X.
ZHUANG 2 ;
1 Psychology, Univ. Michigan, Ann Arbor, MI; 2 Neurobio., Univ. Chicago, Chicago, IL
Abstract: Dopamine has long been thought to be a critical component of the natural reward
pathway, although the exact role it plays in appetitive „wanting‟ versus hedonic „liking‟ remains
undetermined. Mounting evidence points to a role of dopamine levels specifically in the
„wanting‟ of rewards but neither the „liking‟ of them nor the „learning‟ about them. To further
investigate this role, genetic and behavioral approaches were combined. Dopamine transporter