Vitamin D(3) restores altered cholinergic and insulin receptor expression in the cerebral cortex and muscarinic M3 receptor expression in pancreatic islets of streptozotocin induced diabetic rats.
Summary of "Vitamin D(3) restores altered cholinergic and insulin receptor expression in the cerebral cortex and muscarinic M3 receptor expression in pancreatic islets of streptozotocin induced diabetic rats."
Nutritional therapy is a challenging but necessary dimension in the management of diabetes and neurodegenerative changes associated with it. The study evaluates the effect of vitamin D(3) in preventing the altered function of cholinergic, insulin receptors and GLUT3 in the cerebral cortex of diabetic rats. Muscarinic M3 acetylcholine receptors in pancreas control insulin secretion. Vitamin D(3) treatment in M3 receptor regulation in the pancreatic islets was also studied. Radioreceptor binding assays and gene expression was done in the cerebral cortex of male Wistar rats. Immunocytochemistry of muscarinic M3 receptor was studied in the pancreatic islets using specific antibodies. Y-maze was used to evaluate the exploratory and spatial memory. Diabetes induced a decrease in muscarinic M1, insulin and vitamin D receptor expression and an increase in muscarinic M3, alpha7 nicotinic acetylcholine receptor, acetylcholine esterase and GLUT3 expression. Vitamin D(3) and insulin treatment reversed diabetes-induced alterations to near control. Diabetic rats showed a decreased Y-maze performance while vitamin D(3) supplementation improved the behavioural deficit. In conclusion, vitamin D(3) shows a potential therapeutic effect in normalizing diabetes-induced alterations in cholinergic, insulin and vitamin D receptor and maintains a normal glucose transport and utilisation in the cortex. In addition vitamin D(3) modulated muscarinic M3 receptors activity in pancreas and plays a pivotal role in controlling insulin secretion. Hence our findings proved, vitamin D(3) supplementation as a potential nutritional therapy in ameliorating diabetes mediated cortical dysfunctions and suggest an interaction between vitamin D(3) and muscarinic M3 receptors in regulating insulin secretion from pancreas.
Molecular Neurobiology and Cell Biology Unit, Centre for Neuroscience, Cochin University of Science and Technology, Cochin, Kerala 682 022, India.
This article was published in the following journal.
Name: The Journal of nutritional biochemistry
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/20655720
- DOI: http://dx.doi.org/10.1016/j.jnutbio.2010.03.010
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Medical and Biotech [MESH] Definitions
A syndrome with excessively high INSULIN levels in the BLOOD. It may cause HYPOGLYCEMIA. Etiology of hyperinsulinism varies, including hypersecretion of a beta cell tumor (INSULINOMA); autoantibodies against insulin (INSULIN ANTIBODIES); defective insulin receptor (INSULIN RESISTANCE); or overuse of exogenous insulin or HYPOGLYCEMIC AGENTS.
A cell surface receptor for INSULIN. It comprises a tetramer of two alpha and two beta subunits which are derived from cleavage of a single precusor protein. The receptor contains an intrinsic TYROSINE KINASE domain that is located within the beta subunit. Activation of the receptor by INSULIN results in numerous metabolic changes including increased uptake of GLUCOSE into the liver, muscle, and ADIPOSE TISSUE.
Diminished effectiveness of INSULIN in lowering blood sugar levels: requiring the use of 200 units or more of insulin per day to prevent HYPERGLYCEMIA or KETOSIS. It can be caused by the presence of INSULIN ANTIBODIES or the abnormalities in insulin receptors (RECEPTOR, INSULIN) on target cell surfaces. It is often associated with OBESITY; DIABETIC KETOACIDOSIS; INFECTION; and certain rare conditions. (from Stedman, 25th ed)
A structurally-related group of signaling proteins that are phosphorylated by the INSULIN RECEPTOR PROTEIN-TYROSINE KINASE. The proteins share in common an N-terminal PHOSPHOLIPID-binding domain, a phosphotyrosine-binding domain that interacts with the phosphorylated INSULIN RECEPTOR, and a C-terminal TYROSINE-rich domain. Upon tyrosine phosphorylation insulin receptor substrate proteins interact with specific SH2 DOMAIN-containing proteins that are involved in insulin receptor signaling.
A DNA sequence that is found in the promoter region of vitamin D regulated genes. Vitamin D receptor (RECEPTOR, CALCITRIOL) binds to and regulates the activity of genes containing this element.