title: Dopamine signaling in the medial prefrontal cortex and amygdala is required for the acquisition of fructose-conditioned flavor preferences in rats.
abstract: Systemic administration of dopamine (DA) D1 (SCH23390: SCH) and D2 (raclopride: RAC) antagonists blocked both acquisition and expression of fructose-conditioned flavor preferences (CFP). It is unclear what brain circuits are involved in mediating these effects. The present study investigated DA signaling within the nucleus accumbens shell (NAcS), amygdala (AMY) and medial prefrontal cortex (mPFC) in the acquisition and expression of fructose-CFP. In Experiment 1, separate groups of rats were injected daily in the NAcS or AMY with saline, SCH (24 nmol) or RAC (24 nmol) prior to training sessions with a flavor (CS+) mixed with 8% fructose and 0.2% saccharin (CS+/F) and a different flavor (CS-) mixed with only 0.2% saccharin. In the two-bottle choice tests with 0.2% saccharin, only rats injected with RAC in the AMY failed to acquire a CS+ preference (45-54%). In Experiment 2, new rats were identically trained, but saline, SCH and RAC were injected in the mPFC. In subsequent two-bottle choice tests, SCH- and RAC-treated rats failed to exhibit a CS+ preference (50-56%). In Experiment 3, new rats were trained with CS+/F and CS- without injections. Subsequent two-bottle choice tests were then conducted following bilateral injections of SCH or RAC in the mPFC at total doses of 0, 12, 24 and 48 nmol. Expression of the CS+ preference failed to be affected by either antagonist, indicating that the mPFC is not involved in the maintenance of this preference. These data indicate that the acquisition of fructose-CFP is dependent on DA signaling in the mPFC and AMY.
authors.affiliation: Neuropsychology Doctoral Subprogram, Graduate Center, City University of New York, New York, NY, USA.
authors.forename: Danielle C
authors.initials: DC
authors.lastname: Malkusz
authors.forename: Theodore
authors.initials: T
authors.lastname: Banakos
authors.forename: Andrew
authors.initials: A
authors.lastname: Mohamed
authors.forename: Tracy
authors.initials: T
authors.lastname: Vongwattanakit
authors.forename: Gina
authors.initials: G
authors.lastname: Malkusz
authors.forename: Shermeen
authors.initials: S
authors.lastname: Saeed
authors.forename: Stewart
authors.initials: S
authors.lastname: Martinez
authors.forename: Tara
authors.initials: T
authors.lastname: Bohn
authors.forename: Fizza
authors.initials: F
authors.lastname: Mahmud
authors.forename: Cami
authors.initials: C
authors.lastname: Liss
authors.forename: Abraham
authors.initials: A
authors.lastname: Rozvi
authors.forename: Khalid
authors.initials: K
authors.lastname: Touzani
authors.forename: Anthony
authors.initials: A
authors.lastname: Sclafani
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Bodnar
mesh_terms: D000679:Amygdala / Q000502:physiology*; D000704:Analysis of Variance; D000818:Animals; D001552:Benzazepines / Q000494:pharmacology; D003216:Conditioning, Operant / Q000187:drug effects / Q000502:physiology*; D004298:Dopamine / Q000378:metabolism*; D018492:Dopamine Antagonists / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005518:Food Preferences / Q000187:drug effects / Q000502:physiology*; D005632:Fructose / Q000008:administration & dosage; D008297:Male; D017397:Prefrontal Cortex / Q000502:physiology*; D020891:Raclopride / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
chemical_list: D001552:Benzazepines; D018492:Dopamine Antagonists; C534628:SCH 23390; D005632:Fructose; D020891:Raclopride; D004298:Dopamine