Mechanisms of insulin resistance in the amygdala: Influences on food intake

Author(s)

Condes Areias, Maria Fernanda ^[1] ; Prada, Patricia Oliveira ^{[1, 2]}

Affiliation

^[1] Univ Estadual Campinas, Sch Med Sci, Campinas, SP - Brazil

^[2] Univ Estadual Campinas, Sch Appl Sci, BR-13484350 Limeira, SP - Brazil

• Document type: Review article
• Source: Behavioural Brain Research; v. 282, p. 209-217, APR 2015.
• Web of Science Citations: 22

Abstract

Obesity is increasing worldwide and is triggered, at least in part, by enhanced caloric intake. Food intake is regulated by a complex mechanism involving the hypothalamus and hindbrain circuitries. However, evidences have showing that reward systems are also important in regulating feeding behavior. In this context, amygdala is considered a key extra-hypothalamic area regulating feeding behavior in human beings and rodents. This review focuses on the regulation of food intake by amygdala and the mechanisms of insulin resistance in this brain area. Similar to the hypothalamus the anorexigenic effect of insulin is mediated via PI3K (phosphoinositide 3-kinase)/Akt (protein kinase B) pathway in the amygdala. Insulin decreases NPY (neuropeptide Y) and increases oxytocin mRNA levels in the amygdala. High fat diet and saturated fatty acids induce inflammation, ER (endoplasmic reticulum) stress and the activation of serine kinases such as PKC theta (protein kinase C theta), JNK (c-Jun N-terminal kinase) and IKKP (inhibitor of nuclear factor kappa-B kinase beta) in the amygdala, which have an important role in insulin resistance in this brain region. Overexpressed PKCO in the CeA (central nucleus of amygdala) of rats increases weight gain, food intake, insulin resistance and hepatic triglycerides content. The inhibition of ER stress ameliorates insulin action/signaling, increases oxytocin and decreases NPY gene expression in the amygdala of high fat feeding rodents. Those data suggest that PKCO and ER stress are main mechanisms of insulin resistance in the amygdala of obese rats and play an important role regulating feeding behavior. (C) 2015 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 13/07607-8 - OCRC - Obesity and Comorbidities Research Center
• Grantee: Licio Augusto Velloso
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 12/10338-6 - The regulation of Clk2 and IKK epsilon in the hypothalamus of obese mice
• Grantee: Patrícia de Oliveira Prada
• Support Opportunities: Regular Research Grants