Insulin Secretion and Acetylcholinesterase Activity in Monosodium &lt;i&gt;L&lt;/i&gt;-Glutamate-Induced Obese Mice

Balbo, Sandra Lucinei; Gravena, Clarice; Bonfleur, Maria Lúcia; Mathias, Paulo Cézar de Freitas

doi:10.1159/000053257

Cited by 44 publications

(12 citation statements)

References 24 publications

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“…Our study, in addition to detecting morphofunctional alterations in the pancreas of MSG rats, also replicated the obesity parameters that have been previously reported for MSG rats 13 - 15 , 17 , 30 , since MSG rats presented lower values for BW and nasoanal length and increased values for Lee index and fat deposition, normoglycemia, hyperinsulinemia, dyslipidemia, glucose intolerance, and insulin resistance ( Tables 1 and 2 ; Figures 1 and 2 ). Vagotomy, performed at 30 days of age, prevented obesity and improved glucose tolerance and insulin sensitivity in adult Mvag rats ( Tables 1 and 2 , Figures 1 and 2 ).…”

Section: Discussionsupporting

confidence: 89%

“…It is known that, in the postprandial state, the activation of parasympathetic efferent nerves improves the action of insulin in target tissues 32 , 33 . However, in obesity, PNS hyperactivity occurs, leading to an adaptive enhanced acetylcholinesterase activity 15 , 34 ; and this effect may contribute to decreased insulin action and development of type 2 diabetes.…”

Section: Discussionmentioning

confidence: 99%

“…MSG-induced obesity is characterized by hypo- or normophagy ( 13 ), higher fat deposition, glucose intolerance, hyperinsulinemia, and insulin resistance ( 14 ). Furthermore, pancreatic islets from MSG-obese rodents secrete more insulin in response to glucose ( 15 - 17 ) but present a diminished secretory function in response to cholinergic stimulus ( 15 , 18 ). This effect is partly associated with an alteration in ANS action, with a reduction in sympathetic function, but enhanced PNS activity ( 10 ).…”

Section: Introductionmentioning

confidence: 99%

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Vagotomy ameliorates islet morphofunction and body metabolic homeostasis in MSG-obese rats

Lubaczeuski

Balbo

Ribeiro

et al. 2015

Braz J Med Biol Res

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The parasympathetic nervous system is important for β-cell secretion and mass regulation. Here, we characterized involvement of the vagus nerve in pancreatic β-cell morphofunctional regulation and body nutrient homeostasis in 90-day-old monosodium glutamate (MSG)-obese rats. Male newborn Wistar rats received MSG (4 g/kg body weight) or saline [control (CTL) group] during the first 5 days of life. At 30 days of age, both groups of rats were submitted to sham-surgery (CTL and MSG groups) or subdiaphragmatic vagotomy (Cvag and Mvag groups). The 90-day-old MSG rats presented obesity, hyperinsulinemia, insulin resistance, and hypertriglyceridemia. Their pancreatic islets hypersecreted insulin in response to glucose but did not increase insulin release upon carbachol (Cch) stimulus, despite a higher intracellular Ca2+ mobilization. Furthermore, while the pancreas weight was 34% lower in MSG rats, no alteration in islet and β-cell mass was observed. However, in the MSG pancreas, increases of 51% and 55% were observed in the total islet and β-cell area/pancreas section, respectively. Also, the β-cell number per β-cell area was 19% higher in MSG rat pancreas than in CTL pancreas. Vagotomy prevented obesity, reducing 25% of body fat stores and ameliorated glucose homeostasis in Mvag rats. Mvag islets demonstrated partially reduced insulin secretion in response to 11.1 mM glucose and presented normalization of Cch-induced Ca2+ mobilization and insulin release. All morphometric parameters were similar among Mvag and CTL rat pancreases. Therefore, the higher insulin release in MSG rats was associated with greater β-cell/islet numbers and not due to hypertrophy. Vagotomy improved whole body nutrient homeostasis and endocrine pancreatic morphofunction in Mvag rats.

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Section: Discussionsupporting

confidence: 89%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Vagotomy ameliorates islet morphofunction and body metabolic homeostasis in MSG-obese rats

Lubaczeuski

Balbo

Ribeiro

et al. 2015

Braz J Med Biol Res

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“…This was in agreement with the findings of Adefegha and Oboh (2012a) that the inhibitory effect of A. melegueta seed extract on acetylcholinesterase activity could be attributed to the combined effect of the extract"s phenolic and non-phenolic constituents. The result was also in agreement with the findings of Lucinei et al (2000), and Sowmya and Sarada (2015) that the increased in AChE activity in the hippocampus of MSG treated group only was as a result of dysfunction in the cholinergic system, which resulted in alteration of the enzyme.…”

Section: Resultssupporting

confidence: 92%

Neuroprotective potential of Aframomum melegueta extracts on brain of monosodium glutamate-treated wistar albino rats

Fasakin¹,

Fajobi²,

Oyedapo³

2017

J. Neurosci. Behav. Health

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The study evaluated the biochemical effects of methanolic seed extract of Aframomum melegueta (MEAM) on biochemical parameters of the brain of rats treated with monosodium glutamate (MSG) with a view to considering the possibility of using the plant as a remedy for the management of neurotoxic disorders. MEAM was prepared according to standard methods, phytochemically screened and followed by evaluation of its antioxidant and anti-inflammatory potentials as well as its biological activities. Phytochemical screening of the methanolic extract (ME) revealed the presence of alkaloids, cardiac glycosides, flavonoids, saponins, steroids, tannins and terpenoids. Administration of MSG (2 g/kg bwt) caused alterations in the levels of glutathione, nitric oxide, Vitamin C and E, as well as in the reduction of activities of enzymatic antioxidants. There were increases in the activities of brain marker enzymes, protein and peroxidation levels. Histopathological observations of brain sections revealed that MEAM protected the brain from glutamate-induced neurotoxicity. Conclusively, extract of A. melegueta elicited appreciable and potent neuroprotective potentials against neuro-degeneration caused by MSG oral administration, in a concentration dependent manner.

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“…Similar features have been observed in HyO patients (6). Hyperinsulinemia in hypothalamic lesions is frequently associated with the disruption of the autonomic nervous system (ANS) in HyO humans and experimental rodents (29,30). The ANS dysfunction is characterized by a lower inhibitory sympathetic tone, associated with an augmented vagal parasympathetic signaling to the pancreatic β-cells.…”

Section: Discussionmentioning

confidence: 99%

Duodenal-jejunal bypass normalizes pancreatic islet proliferation rate and function but not hepatic steatosis in hypothalamic obese rats

Cantelli

Soares

Ribeiro

et al. 2017

Braz J Med Biol Res

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Modifications in life-style and/or pharmacotherapies contribute to weight loss and ameliorate the metabolic profile of diet-induced obese humans and rodents. Since these strategies fail to treat hypothalamic obesity, we have assessed the possible mechanisms by which duodenal-jejunal bypass (DJB) surgery regulates hepatic lipid metabolism and the morphophysiology of pancreatic islets, in hypothalamic obese (HyO) rats. During the first 5 days of life, male Wistar rats received subcutaneous injections of monosodium glutamate (4 g/kg body weight, HyO group), or saline (CTL). At 90 days of age, HyO rats were randomly subjected to DJB (HyO DJB group) or sham surgery (HyO Sham group). HyO Sham rats were morbidly obese, insulin resistant, hypertriglyceridemic and displayed higher serum concentrations of non-esterified fatty acids (NEFA) and hepatic triglyceride (TG). These effects were associated with higher expressions of the lipogenic genes and fatty acid synthase (FASN) protein content in the liver. Furthermore, hepatic genes involved in β-oxidation and TG export were down-regulated in HyO rats. In addition, these rats exhibited hyperinsulinemia, β-cell hypersecretion, a higher percentage of islets and β-cell area/pancreas section, and enhanced nuclear content of Ki67 protein in islet-cells. At 2 months after DJB surgery, serum concentrations of TG and NEFA, but not hepatic TG accumulation and gene and protein expressions, were normalized in HyO rats. Insulin release and Ki67 positive cells were also normalized in HyO DJB islets. In conclusion, DJB decreased islet-cell proliferation, normalized insulinemia, and ameliorated insulin sensitivity and plasma lipid profile, independently of changes in hepatic metabolism.

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Insulin Secretion and Acetylcholinesterase Activity in Monosodium <i>L</i>-Glutamate-Induced Obese Mice

Cited by 44 publications

References 24 publications

Vagotomy ameliorates islet morphofunction and body metabolic homeostasis in MSG-obese rats

Vagotomy ameliorates islet morphofunction and body metabolic homeostasis in MSG-obese rats

Neuroprotective potential of Aframomum melegueta extracts on brain of monosodium glutamate-treated wistar albino rats

Duodenal-jejunal bypass normalizes pancreatic islet proliferation rate and function but not hepatic steatosis in hypothalamic obese rats

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