title: Vagotomy ameliorates islet morphofunction and body metabolic homeostasis in MSG-obese rats.
abstract: 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 Ca(2+) 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 Ca(2+) 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.
authors.affiliation: Laboratório de Fisiologia Endócrina e Metabolismo, Centro de Ciências Biológicas e da Saúde, Universidade Estadual do Oeste do Paraná, Cascavel, PR, Brasil.
authors.forename: C
authors.initials: C
authors.lastname: Lubaczeuski
authors.affiliation: Laboratório de Fisiologia Endócrina e Metabolismo, Centro de Ciências Biológicas e da Saúde, Universidade Estadual do Oeste do Paraná, Cascavel, PR, Brasil.
authors.forename: S L
authors.initials: SL
authors.lastname: Balbo
authors.affiliation: Universidade Federal do Rio de Janeiro, Macaé, RJ, Brasil.
authors.forename: R A
authors.initials: RA
authors.lastname: Ribeiro
authors.affiliation: Departamento de Biologia Estrutural e Funcional, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, SP, Brasil.
authors.forename: J F
authors.initials: JF
authors.lastname: Vettorazzi
authors.affiliation: Departamento de Biologia Estrutural e Funcional, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, SP, Brasil.
authors.forename: J C
authors.initials: JC
authors.lastname: Santos-Silva
authors.affiliation: Departamento de Biologia Estrutural e Funcional, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, SP, Brasil.
authors.forename: E M
authors.initials: EM
authors.lastname: Carneiro
authors.affiliation: Laboratório de Fisiologia Endócrina e Metabolismo, Centro de Ciências Biológicas e da Saúde, Universidade Estadual do Oeste do Paraná, Cascavel, PR, Brasil.
authors.forename: M L
authors.initials: ML
authors.lastname: Bonfleur
mesh_terms: D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D002452:Cell Count; D002784:Cholesterol / Q000032:analysis; D018679:Cholinergic Agonists / Q000494:pharmacology; D005421:Flavoring Agents / Q000494:pharmacology; D005947:Glucose / Q000378:metabolism; D006706:Homeostasis / Q000502:physiology*; D006946:Hyperinsulinism / Q000503:physiopathology*; D007328:Insulin / Q000378:metabolism*; D007333:Insulin Resistance / Q000502:physiology; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000187:drug effects / Q000378:metabolism; D007515:Islets of Langerhans / Q000294:innervation / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D009765:Obesity / Q000139:chemically induced / Q000503:physiopathology*; D010179:Pancreas / Q000473:pathology; D017208:Rats, Wistar; D012970:Sodium Glutamate / Q000494:pharmacology; D014280:Triglycerides / Q000032:analysis; D014628:Vagotomy; D014630:Vagus Nerve / Q000502:physiology
chemical_list: D018679:Cholinergic Agonists; D005421:Flavoring Agents; D007328:Insulin; D014280:Triglycerides; D002217:Carbachol; D002784:Cholesterol; D005947:Glucose; D012970:Sodium Glutamate