title: Nucleus accumbens shell and core dopamine responsiveness to sucrose in rats: role of response contingency and discriminative/conditioned cues.
abstract: This study investigated by microdialysis the role of response contingency and food-associated cues in the responsiveness of dopamine transmission in the nucleus accumbens shell and core to sucrose feeding. In naive rats, single-trial non-contingent presentation and feeding of sucrose pellets increased dialysate shell dopamine and induced full habituation of dopamine responsiveness to sucrose feeding 24 and 48 h later. In rats trained to respond for sucrose pellets on a fixed ratio 1 (FR1) schedule, dialysate dopamine increased in the shell but not in the core during active responding as well as under extinction in the presence of sucrose cues. In rats yoked to the operant rats, the presentation of sucrose cues also increased dialysate dopamine selectively in the shell. In contrast, non-contingent sucrose presentation and feeding in FR1-trained and in yoked rats increased dialysate dopamine to a similar extent in the shell and core. It is concluded that, whereas non-contingent sucrose feeding activated dopamine transmission in the shell and core, response-contingent feeding activated, without habituation, dopamine transmission selectively in the shell as a result of the action of sucrose conditioned cues. These observations are consistent with a critical role of conditioned cues acquired during training and differential activation of shell vs. core dopamine for response-contingent sucrose feeding.
authors: Department of Biomedical Sciences, University of Cagliari, Via Ospedale 72, 09124, Cagliari, Italy; National Institute of Neuroscience, University of Cagliari, Cagliari, Italy.
authors: V
authors: V
authors: Bassareo
authors: F
authors: F
authors: Cucca
authors: P
authors: P
authors: Musio
authors: D
authors: D
authors: Lecca
authors: R
authors: R
authors: Frau
authors: G
authors: G
authors: Di Chiara
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D003216:Conditioning, Operant / Q000502:physiology*; D003463:Cues; D004298:Dopamine / Q000032:analysis / Q000502:physiology*; D005108:Extinction, Psychological / Q000502:physiology; D008297:Male; D017551:Microdialysis; D009714:Nucleus Accumbens / Q000737:chemistry / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012055:Reinforcement Schedule; D013395:Sucrose
chemical_list: D013395:Sucrose; D004298:Dopamine
keywords: food; mesolimbic system; self-administration