Neuroprotective role of curcumin in the cerebellum of streptozotocin-induced diabetic rats

Aims: Chronic hyperglycaemia in diabetes involves a direct neuronal damage Caused by intracellular glucose which leads to altered neurotransmitter functions and reduced motor activity. The present Study investigated the effect of curcumin in the functional regulation Of muscarinic and alpha 7 nicotinic acetylcholine receptors, insulin receptors, acetylcholine esterase and Glut3 in the cerebellum of streptozotocin (STZ)-induced diabetic rats. Main methods: All Studies were done in the cerebellum of male Wistar rats. Radioreceptor binding assays were done for total muscarinic, M-1 and M-3 receptors using specific ligands, and the gene expression was also studied using specific probes. Key findings: Our results showed an increased gene expression of acetylcholine esterase. Glut3, muscarinic M-1, M-3, alpha 7 nicotinic acetylcholine and insulin receptors in the cerebellum of diabetic rats in comparison to control. Scatchard analysis of total muscarinic. M-1 and M-3 receptors showed an increased binding parameter, B-max in diabetic rats compared to control. Curcumin and insulin inhibited diabetes-induced elevation in the gene expression of acetylcholine esterase, Glut3, insulin and cholinergic receptors in the cerebellum of diabetic rats. Significance: Our studies Suggest that curcumin plays a vital role in regulating the activity of cholinergic and insulin receptors and mechanism of glucose transportation through Glut3, which results in normalizing the diabetes-mediated cerebellar disorders. Thus, curcumin has a significant role in a therapeutic application for the prevention or progression of diabetic complications in the cerebellum. (C) 2009 Elsevier Inc. All rights reserved.