Background/aims: Impaired pancreatic beta cell function and insulin secretion/action are a link between obesity and type 2 diabetes, which are worldwide public health burdens. We aimed to characterize the muscarinic acetylcholine receptor (mAChR) M1-M4 subtypes in isolated pancreatic islets from pre-diabetic obese rats that had been treated neonatally with monosodium L-glutamate (MSG).
Methods: At 90 days of age, both the MSG and the control groups underwent biometric and biochemical evaluation. Anti-muscarinic drugs were used to study mAChR function either in vivo or in vitro.
Results: The results demonstrated that atropine treatment reduced insulin secretion in the MSG-treated and control groups, whereas treatment with an M2mAChR-selective antagonist increased secretion. Moreover, the insulinostatic effect of an M3mAChR-selective antagonist was significantly higher in the MSG-treated group. M1mAChR and M3mAChR expression was increased in the MSG-obese group by 55% and 73%, respectively. In contrast, M2mAChR expression decreased by 25% in the MSG group, whereas M4mAChR expression was unchanged.
Conclusions: Functional changes in and altered content of the mAChR (M1-M4) subtypes are pivotal to the demand for high pancreatic beta cell insulin secretion in MSG-obese rats, which is directly associated with vagal hyperactivity and peripheral insulin resistance.
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Toxicon
January 2025
Universidade Estadual do Oeste do Paraná, Programa de Pós-Graduação em Biociências e Saúde (PPG-BCS) - Cascavel, Brazil. Electronic address:
This study investigated the effects of a novel bombesin-related peptide (BR-b), derived from the skin of the Chaco tree frog (Boana raniceps), on glucose homeostasis in non-obese and hypothalamic-obese male rats. Hypothalamic obesity was induced in neonatal rats through high-dose administration of monosodium glutamate (MSG; 4 g/kg), while control animals (CTL) received an equimolar saline solution. At 70 days of age, both MSG and CTL groups underwent an oral glucose tolerance test (OGTT; 2 g/kg) with or without prior intraperitoneal administration of BR-b at doses of 0.
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August 2023
Laboratory of Pharmacology, Instituto Butantan.
Here, we investigate the effects of obesity induced by monosodium glutamate (MSG) on cognitive impairment and whether this model induces any alteration in the affinity, density, and subtypes of muscarinic acetylcholine receptors (mAChRs) in rat hippocampus. Healthy rats were used as controls, and MSG-obese rats were selected via the Lee index > 0.300.
View Article and Find Full Text PDFIran J Basic Med Sci
July 2022
Department of Pharmacology, School of Pharmaceutical Education & Research (SPER), Jamia Hamdard, (UGC approved deemed to be University, Govt. of India), New Delhi-110062, India.
Pharmaceutics
July 2021
Pharmacology of Bioactive Products Research Group, Federal University of Rio de Janeiro-Macaé Campus, Macaé 27930-560, RJ, Brazil.
Endothelial dysfunction in obesity plays a key role in the development of cardiovascular diseases, and it is characterized by increased vascular tonus and oxidative stress. Thus, this study aimed to investigate the vasodilatory and antioxidant activities of ethyl acetate fraction and subfractions. Vascular effects were investigated on aorta isolated from control and monosodium glutamate (MSG) induced-obese Wistar rats, and antioxidant activity was assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and oxygen radical absorbance capacity (ORAC) methods.
View Article and Find Full Text PDFFront Endocrinol (Lausanne)
January 2022
Laboratory of Secretion Cell Biology, Department of Biotechnology, Genetics and Cell Biology, State University of Maringá, Maringá, Brazil.
Metformin is an antidiabetic drug used for the treatment of diabetes and metabolic diseases. Imbalance in the autonomic nervous system (ANS) is associated with metabolic diseases. This study aimed to test whether metformin could improve ANS function in obese rats.
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