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Front. Psychol. | doi: 10.3389/fpsyg.2019.01966

Reduced sensory–evoked locus coeruleus-norepinephrine neural activity in female rats with a history of dietary-induced binge eating

  • 1Rutgers University, The State University of New Jersey, United States

Noradrenergic pathways have been implicated in eating pathologies. These experiments sought to examine how dietary-induced binge eating influences the neuronal activity of the locus coeruleus (LC)-norepinephrine system. Young adult female Sprague Dawley rats (7-8 weeks old) were exposed to a repeated intermittent (twice weekly) cycle of 30-min access to a highly palatable sweetened fat (i.e., vegetable shortening with 10% sucrose) with or without intermittent (24 h) calorie restriction (Restrict Binge or Binge groups, respectively). Age- and weight-matched female control rats were exposed to standard chow feeding (Naive group) or intermittent chow feeding (Restrict group). The Binge and Restrict Binge groups demonstrated an escalation in sweet-fat food intake after 2.5 weeks. On week 3, in vivo single unit LC electrophysiological activity was recorded under isoflurane anesthesia. Restrict Binge (20 cells from 6 rats), and Binge (27 cells from 6 rats) had significantly reduced (approximate 20% and 26%, respectively) evoked LC discharge rates compared with naive rats (22 cells, 7 rats). Spontaneous and tonic discharge rates were not different among the groups. Signal-to-noise ratio was reduced in the groups with intermittent sweetened fat exposure. In order to investigate the neuropeptide alterations as a consequence of dietary binge eating, relative gene expression of neuropeptide Y (NPY), glucagon-like peptide 1 receptor (GLP-1r), prodynorphin, and related genes were measured in LC and hypothalamic arcuate (Arc) regions. Glp-1r, Npy2r, and Pdyn in LC region were reduced with repeated intermittent restriction. Npy1r was reduced by approximately 27% in ARC of Restrict compared with Naive group. Such data indicate that dietary-induced binge eating alters the neural response of LC neurons to sensory stimuli and dampen the neural stress response.

Keywords: Stress axis, eating pathologies, Binge Eating Disorder, Bulimia, locus ceruleus.

Received: 29 Apr 2019; Accepted: 09 Aug 2019.

Edited by:

Antonios Dakanalis, MD, PsyD, PhD, University of Milano-Bicocca, Italy

Reviewed by:

Carlo Cifani, University of Camerino, Italy
Jonathan Hommel, University of Texas Medical Branch at Galveston, United States
Kristen M. Culbert, University of Nevada, Las Vegas, United States  

Copyright: © 2019 Bello, James and Yeh. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Dr. Nicholas T. Bello, Rutgers University, The State University of New Jersey, New Brunswick, United States, ntbello@aesop.rutgers.edu