High-fructose diet initiated during adolescence does not affect basolateral amygdala excitability or affective-like behavior in Sprague Dawley rats

• Type of Material: Article
• Authors: Brendan O'Flaherty, Emory University; Gretchen Neigh, Emory University; Donald Rainnie, Emory University
• Language: English
• Date: 2019-06-03
• Publisher: Elsevier Science B.V.
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2019 Elsevier B.V. All rights reserved.
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1016/j.bbr.2019.02.042
• Title of Journal or Parent Work: Behavioral Brain Research
• Volume: 365
• Start Page: 17
• End Page: 25
• Grant/Funding Information: This research was supported by the NIH Grant 5F31MH111224-02 to BMO, NIH Grant 5R01MH0698520-12 to DGR, and the NIH Yerkes National Primate Research Center Base Grant RR-00165.
• Keywords: High fat; Corn syrup; Prevalence; Behavioral Sciences; Anxiety; Life Sciences & Biomedicine; Enrichment analysis; Neurosciences; Wistar; Insulin resistance; Science & Technology; Neurosciences & Neurology; Open field; Metabolic syndrome; Depressive behavior; Depression; Forced swim test; Fructose; Sprague Dawley; Amygdala
• Research Categories: Health Sciences, Public Health; Psychology, Behavioral; Health Sciences, Nutrition; Biology, Neuroscience

Abstract

Patients with type-2 diabetes, obesity, and metabolic syndrome have a significantly increased risk of developing depression. Dysregulated metabolism may contribute to the etiology of depression by affecting neuronal activity in key limbic areas. The basolateral amygdala (BLA) acts as a critical emotional valence detector in the brain's limbic circuit, and shows hyperactivity and abnormal glucose metabolism in depressed patients. Furthermore, administering a periadolescent high-fructose diet (HFrD; a model of metabolic syndrome) to male Wistar rats increases anxiety- and depressive-like behavior. Repeated shock stress in Sprague Dawley rats similarly increases anxiety-like behavior and increases BLA excitability. We therefore investigated whether a metabolic stressor (HFrD) would have similar effects as shock stress on BLA excitability in Sprague Dawley rats. We found that a HFrD did not affect the intrinsic excitability of BLA neurons. Fructose-fed Sprague Dawley rats had elevated body fat mass, but did not show increases in metabolic efficiency and fasting blood glucose relative to control. Finally unlike Wistar rats, fructose-fed Sprague Dawley rats did not show increased anxiety- and depressive-like behavior. These results suggest that genetic differences between rat strains may affect susceptibility to a metabolic insult. Collectively, these data show that a periadolescent HFrD disrupts metabolism, but does not change affective behavior or BLA excitability in Sprague Dawley rats.