title: Vitamin D3 supplementation increases insulin level by regulating altered IP3 and AMPA receptor expression in the pancreatic islets of streptozotocin-induced diabetic rat.
abstract: Pancreatic islets, particularly insulin-secreting β cells, share common characteristics with neurons. Glutamate is one of the major excitatory neurotransmitter in the brain and pancreas, and its action is mediated through glutamate receptors. In the present work, we analysed the role of vitamin D3 in the modulation of AMPA receptor subunit and their functional role in insulin release. Radio receptor binding study in diabetic rats showed a significant increase in AMPA receptor density. Insulin AMPA colabelling study showed an altered AMPA GluR2 and GluR4 subunit expression in the pancreatic beta cells. We also found lowered IP3 content and decreased IP3 receptor in pancreas of diabetic rats. The alterations in AMPA and IP3 receptor resulted in reduced cytosolic calcium level concentration, which further blocks Ca(2+)-mediated insulin release. Vitamin D3 supplementation restored the alteration in vitamin D receptor expression, AMPA receptor density and AMPA and IP3 receptor expression in the pancreatic islets that helps to restore the calcium-mediated insulin secretion. Our study reveals the antidiabetic property of vitamin D3 that is suggested to have therapeutic role through regulating glutamatergic function in diabetic rats.
authors.affiliation: Molecular Neurobiology and Cell Biology Unit, Centre for Neuroscience, Cochin University of Science and Technology, Cochin, 682 022, Kerala, India.
authors.forename: Sadanandan
authors.initials: S
authors.lastname: Jayanarayanan
authors.affiliation: Molecular Neurobiology and Cell Biology Unit, Centre for Neuroscience, Cochin University of Science and Technology, Cochin, 682 022, Kerala, India.
authors.forename: Thoppil R
authors.initials: TR
authors.lastname: Anju
authors.affiliation: Molecular Neurobiology and Cell Biology Unit, Centre for Neuroscience, Cochin University of Science and Technology, Cochin, 682 022, Kerala, India.
authors.forename: Soman
authors.initials: S
authors.lastname: Smijin
authors.affiliation: Molecular Neurobiology and Cell Biology Unit, Centre for Neuroscience, Cochin University of Science and Technology, Cochin, 682 022, Kerala, India. Electronic address: cspaulose@cusat.ac.in.
authors.forename: Cheramadathikudiyil Skaria
authors.initials: CS
authors.lastname: Paulose
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D002118:Calcium / Q000032:analysis; D002762:Cholecalciferol / Q000008:administration & dosage*; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000378:metabolism*; D019587:Dietary Supplements; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000032:analysis* / Q000378:metabolism; D007328:Insulin / Q000097:blood*; D007515:Islets of Langerhans / Q000737:chemistry*; D008297:Male; D011869:Radioligand Assay; D051381:Rats; D017208:Rats, Wistar; D018091:Receptors, AMPA / Q000032:analysis* / Q000378:metabolism
chemical_list: D001786:Blood Glucose; D053496:Inositol 1,4,5-Trisphosphate Receptors; D007328:Insulin; D018091:Receptors, AMPA; C104724:glutamate receptor ionotropic, AMPA 4; D002762:Cholecalciferol; C104722:glutamate receptor ionotropic, AMPA 2; D002118:Calcium
keywords: AMPA receptor; Diabetes; IP3; Insulin; Pancreatic islets; Vitamin D(3)