withanolides and Epilepsy--Temporal-Lobe

The aim of this study was to investigate the effect of Withania somnifera (WS) extract, withanolide A (WA), and carbamazepine (CBZ) on cerebellar AMPA receptor function in pilocarpine-induced temporal lobe epilepsy (TLE). In the present study, motor learning deficit was studied by rotarod test, grid walk test, and narrow beam test. Motor learning was significantly impaired in rats with epilepsy. The treatment with WS and WA significantly reversed the motor learning deficit in rats with epilepsy when compared with control rats. There was an increase in glutamate content and IP3 content observed in rats with epilepsy which was reversed in WS- and WA-treated rats with epilepsy. alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor dysfunction was analyzed using radiolabeled AMPA receptor binding assay, AMPA receptor mRNA expression, and immunohistochemistry using anti-AMPA receptor antibody. Our results suggest that there was a decrease in Bmax, mRNA expression, and AMPA receptor expression indicating AMPA receptor dysfunction, which is suggested to have contributed to the motor learning deficit observed in rats with epilepsy. Moreover, treatment with WS and WA resulted in physiological expression of AMPA receptors. There was also alteration in GAD and GLAST expression which supplemented the increase in extracellular glutamate. The treatment with WS and WA reversed the GAD and GLAST expression. These findings suggest that WS and WA regulate AMPA receptor function in the cerebellum of rats with TLE, which has therapeutic application in epilepsy.

Topics: alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; Animals; Anticonvulsants; Carbamazepine; Cerebellum; Disease Models, Animal; Epilepsy, Temporal Lobe; Excitatory Amino Acid Transporter 1; Gene Expression Regulation; Glutamate Decarboxylase; Glutamic Acid; Inositol 1,4,5-Trisphosphate; Learning Disabilities; Linear Models; Locomotion; Male; Motor Activity; Phytotherapy; Pilocarpine; Protein Binding; Psychomotor Performance; Rats; Rats, Wistar; Receptors, AMPA; RNA, Messenger; Time Factors; Tritium; Withania; Withanolides

In the present study we investigate the effect of Withania somnifera (WS) root extract and Withanolide A (WA) in restoring spatial memory deficit by inhibiting oxidative stress induced alteration in glutamergic neurotransmission. We demonstrate significant cellular loss in hippocampus of epileptic rats, visualized through decreased TOPRO stained neurons. Impaired spatial memory was observed in epileptic rats after Radial arm maze test. Treatment with WS and WA has resulted in increased number of TOPRO stained neurons. Enhanced performance of epileptic rats treated with WS and WA was observed in Radial arm maze test. The antioxidant activity of WS and WA was studied using superoxide dismutase (SOD) and Catalase (CAT) assays in the hippocampus of experimental rats. The SOD activity and CAT activity decreased significantly in epileptic group, treatment with WS and WA significantly reversed the enzymatic activities to near control. Real time gene expression studies of SOD and GPx showed significant up-regulation in epileptic group compared to control. Treatment with WS and WA showed significant reversal to near control. Lipid peroxidation quantified using TBARS assay, significantly increased in epileptic rats. Treatment with WS and WA showed significant reversal to near control. NMDA receptor expression decreased in epileptic rats. The treatment with WS and WA resulted in physiological expression of NMDA receptors. This data suggests that oxidative stress effects membrane constitution resulting in decreased NMDA receptor density leading to impaired spatial memory. Treatment with WS and WA has ameliorated spatial memory deficits by enhancing antioxidant system and restoring altered NMDA receptor density.

Topics: Animals; Catalase; Cognition Disorders; Dizocilpine Maleate; Epilepsy, Temporal Lobe; Excitatory Amino Acid Antagonists; Excitatory Amino Acid Transporter 1; Hemostasis; Immunohistochemistry; Male; Maze Learning; Memory Disorders; Oxidative Stress; Plant Roots; Rats; Rats, Wistar; Real-Time Polymerase Chain Reaction; Receptors, N-Methyl-D-Aspartate; Space Perception; Superoxide Dismutase; Thiobarbituric Acid Reactive Substances; Withania; Withanolides