Elsevier

Physiology & Behavior

Volume 180, 15 October 2017, Pages 91-97
Physiology & Behavior

Diet-induced obesity alters memory consolidation in female rats

https://doi.org/10.1016/j.physbeh.2017.08.011Get rights and content
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Highlights

  • Obesity leads to inflammation.

  • Insulin and leptin resistance may be associated with cognitive dysfunctions.

  • Hypercaloric diet was associated with increased weight gain in female rats.

  • Hypercaloric diet impaired memory consolidation in the object recognition test.

  • These changes were accompanied by increased serum levels of glucose and leptin.

Abstract

Obesity is a multifactorial disease characterized by the abnormal or excessive fat accumulation, which is caused by an energy imbalance between consumed and expended calories. Obesity leads to an inflammatory response that may result in peripheral and central metabolic changes, including insulin and leptin resistance. Insulin and leptin resistance have been associated with metabolic and cognitive dysfunctions. Obesity and some neurodegenerative diseases that lead to dementia affect mainly women. However, the effects of diet-induced obesity on memory consolidation in female rats are poorly understood. Therefore, the aim of this study was to evaluate the effect of a hypercaloric diet on the object recognition memory of female rats and on possible related metabolic changes. The animals submitted to the hypercaloric diet presented a higher food intake in grams and in calories, resulting in increased weight gain and liposomatic index in comparison with the animals exposed to the control diet. These animals presented a memory deficit in the object recognition test and increased serum levels of glucose and leptin. However, no significant differences were found in the serum levels of insulin, TNF-α and IL-1β, in the index of insulin resistance (HOMA), in the hippocampal levels of insulin, TNF-α and IL-1β, as well as on Akt expression or activation in the hippocampus. Our findings indicate that adult female rats submitted to a hypercaloric diet present memory consolidation impairment, which could be associated with diet-induced weight gain and leptin resistance, even without the development of insulin resistance.

Keywords

Hypercaloric diet
Leptin
Cognition
Adipokine
Object recognition test

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