Insulin treatment prevents diabetes-induced alterations in astrocyte glutamate uptake and GFAP content in rats at 4 and 8 weeks of diabetes duration.
Rat astrocyte function is changed by diabetes mellitus relative to the nondiabetic state and we believe that altered function contributes to the central nervous system symptoms manifested by individuals with diabetes. We report here a comparison of astrocyte glutamate uptake and GFAP expression in streptozotocin-induced type 1 diabetic rats and insulin-treated diabetic rats at 4 and 8 weeks following diabetes onset. In glial plasmalemmal vesicle (GPV) preparations from treated rats, insulin prevented the increase observed in untreated, diabetic rats of both sodium-dependent and sodium-independent glutamate uptake. We determined by immunoblotting and immunohistochemistry that insulin treatment prevented the decrease of GFAP expression detected in the cerebral cortex, hippocampus, and cerebellum of untreated, diabetic rats. These observations indicate that insulin effects on astrocyte function are significant in managing diabetes-induced central nervous system pathology.
Coleman
Elaine S
ES
Department of Anatomy, Physiology, and Pharmacology, College of Veterinary Medicine, 109 Greene Hall, Auburn University, Auburn, AL 36849, USA. colemes@auburn.edu
Dennis
John C
JC
Braden
Timothy D
TD
Judd
Robert L
RL
Posner
Phil
P
D000818:Animals; D001253:Astrocytes / Q000187:drug effects* / Q000378:metabolism; D015153:Blotting, Western; D002531:Cerebellum / Q000187:drug effects / Q000378:metabolism; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy* / Q000378:metabolism; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism*; D018698:Glutamic Acid / Q000378:metabolism*; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D007150:Immunohistochemistry; D007328:Insulin / Q000494:pharmacology*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012964:Sodium / Q000378:metabolism; D013997:Time Factors
D005904:Glial Fibrillary Acidic Protein; D007004:Hypoglycemic Agents; D007328:Insulin; D018698:Glutamic Acid; D012964:Sodium