title: Episodic sucrose intake during food restriction increases synaptic abundance of AMPA receptors in nucleus accumbens and augments intake of sucrose following restoration of ad libitum feeding.
abstract: Weight-loss dieting often leads to loss of control, rebound weight gain, and is a risk factor for binge pathology. Based on findings that food restriction (FR) upregulates sucrose-induced trafficking of glutamatergic AMPA receptors to the nucleus accumbens (NAc) postsynaptic density (PSD), this study was an initial test of the hypothesis that episodic "breakthrough" intake of forbidden food during dieting interacts with upregulated mechanisms of synaptic plasticity to increase reward-driven feeding. Ad libitum (AL) fed and FR subjects consumed a limited amount of 10% sucrose, or had access to water, every other day for 10 occasions. Beginning three weeks after return of FR rats to AL feeding, when 24-h chow intake and rate of body weight gain had normalized, subjects with a history of sucrose intake during FR consumed more sucrose during a four week intermittent access protocol than the two AL groups and the group that had access to water during FR. In an experiment that substituted noncontingent administration of d-amphetamine for sucrose, FR subjects displayed an enhanced locomotor response during active FR but a blunted response, relative to AL subjects, during recovery from FR. This result suggests that the enduring increase in sucrose consumption is unlikely to be explained by residual enhancing effects of FR on dopamine signaling. In a biochemical experiment which paralleled the sucrose behavioral experiment, rats with a history of sucrose intake during FR displayed increased abundance of pSer845-GluA1, GluA2, and GluA3 in the NAc PSD relative to rats with a history of FR without sucrose access and rats that had been AL throughout, whether they had a history of episodic sucrose intake or not. A history of FR, with or without a history of sucrose intake, was associated with increased abundance of GluA1. A terminal 15-min bout of sucrose intake produced a further increase in pSer845-GluA1 and GluA2 in subjects with a history of sucrose intake during FR. Generally, neither a history of sucrose intake nor a terminal bout of sucrose intake affected AMPA receptor abundance in the NAc PSD of AL subjects. Together, these results are consistent with the hypothesis, but the functional contribution of increased synaptic incorporation of AMPA receptors remains to be established.
authors: Department of Psychiatry, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA.
authors: X-X
authors: XX
authors: Peng
authors: Department of Psychiatry, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA.
authors: A
authors: A
authors: Lister
authors: Department of Psychiatry, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA.
authors: A
authors: A
authors: Rabinowitsch
authors: Department of Psychiatry, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA.
authors: R
authors: R
authors: Kolaric
authors: Department of Psychiatry, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA.
authors: S
authors: S
authors: Cabeza de Vaca
authors: Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA.
authors: E B
authors: EB
authors: Ziff
authors: Department of Psychiatry, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA; Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA. Electronic address: Kenneth.Carr@nyumc.org.
authors: K D
authors: KD
authors: Carr
mesh_terms: D000661:Amphetamine / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D001835:Body Weight / Q000187:drug effects / Q000502:physiology; D000697:Central Nervous System Stimulants / Q000494:pharmacology; D004435:Eating / Q000187:drug effects / Q000502:physiology; D005247:Feeding Behavior / Q000187:drug effects / Q000502:physiology*; D005508:Food Deprivation / Q000502:physiology*; D006948:Hyperkinesis / Q000139:chemically induced; D008297:Male; D009714:Nucleus Accumbens / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D057907:Post-Synaptic Density / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018091:Receptors, AMPA / Q000378:metabolism*; D013347:Subcellular Fractions; D013395:Sucrose / Q000008:administration & dosage*; D013549:Sweetening Agents / Q000008:administration & dosage*; D013997:Time Factors
chemical_list: D000697:Central Nervous System Stimulants; D018091:Receptors, AMPA; D013549:Sweetening Agents; D013395:Sucrose; D000661:Amphetamine
keywords: AMPA receptors; food restriction; nucleus accumbens; postsynaptic density; sucrose