Premium
Vagus nerve contributes to metabolic syndrome in high‐fat diet‐fed young and adult rats
Author(s) -
Barella Luiz F.,
Miranda Rosiane A.,
Franco Claudinéia C. S.,
Alves Vander S.,
Malta Ananda,
Ribeiro Tatiane A. S.,
Gravena Clarice,
Mathias Paulo C. F.,
de Oliveira Júlio C.
Publication year - 2014
Publication title -
experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0958-0670
DOI - 10.1113/expphysiol.2014.082982
Subject(s) - vagotomy , endocrinology , medicine , vagus nerve , obesity , endocrine system , adipose tissue , insulin resistance , weaning , autonomic nervous system , parasympathetic nervous system , sympathetic nervous system , stimulation , blood pressure , heart rate , hormone
New FindingsWhat is the central question of this study? Differentnerve contributes periods of life are known for their differential sensitivity to interventions, and increased parasympathetic activity affects the development and maintenance of obesity. Thus, we evaluated the involvement of the vagus nerve by performing a vagotomy in young or adult rats that were offered an obesogenic high‐fat diet.What is the main finding and its importance? Although the accumulation of adipose tissue decreased in both younger and older groups, the younger rats showed a greater response to the effects of vagotomy in general. In addition to the important role of the parasympathetic activity, we suggest that the vagus nerve contributes to the condition of obesity.Obesity has become a global problem, and this condition develops primarily because of an imbalance between energy intake and expenditure. The high complexity involved in the regulation of energy metabolism results from several factors besides endocrine factors. It has been suggested that obesity could be caused by an imbalance in the autonomous nervous system, which could lead to a condition of high parasympathetic activity in counterpart to low sympathetic tonus. High‐fat (HF) diets have been used to induce obesity in experimental animals, and their use in animals leads to insulin resistance, hyperinsulinaemia and high parasympathetic activity, among other disorders. The aim of this work was to evaluate the effects of a vagotomy performed at the initiation of a HF diet at two different stages of life, weaning and adulthood. The vagotomy reduced parasympathetic activity (−32 and −51% in normal fat‐fed rats and −43 and −55% in HF diet‐fed rats; P < 0.05) and fat depots (−17 and −33%, only in HF diet‐fed rats; P < 0.05). High‐fat diet‐fed rats exhibited fasting hyperinsulinaemia (fivefold higher in young rats and threefold higher in older rats; P < 0.05); however, vagotomy corrected it in younger rats only, and a similar effect was also observed during the glucose tolerance test. The insulin resistance exhibited by the HF diet‐fed groups was not altered in the vagotomized rats. We suggest that the vagus nerve, in addition to the important role of parasympathetic activity, contributes to the condition of obesity, and that non‐vagal pathways may be involved along with the imbalanced autonomic nervous system.