Handbook of Vitamin C Research

In: Handbook of Vitamin C Research ISBN: 978-1-60741-874-0Editors: Hubert Kucharski and Julek Zajac©2009 Nova Science Publishers, Inc.Chapter XIEffects of Vitamin C on OxidativeStress-Induced MolecularPathways in EpilepsyMustafa NazıroğluDepartment of Biophysics, Medical Faculty, Süleyman Demirel University,Isparta, TurkeyAbstractEpileptic seizures result from excessive discharge in a population of hyperexcitableneurons. Excessive production of ROS (reactive oxygen species) is thought to contributeto epilepsy, and there is a potential connection between ROS and mitochondrialdysfunction in epilepsy. Free radical generation can also induce seizure activity by directactivation of glutamine synthatase, thereby permitting an abnormal buildup of glutamicacid, the excitatory neurotransmitter. The brain is extremely susceptible to oxidativedamage induced by these ROS because it generates extremely high levels of ROS due toits very high aerobic metabolism and blood perfusion, and it has a relatively poorenzymatic antioxidant defense. Recent research on vitamin C (ascorbic acid, orascorbate) has pointed out novel mechanisms of its action such as that of neuromodulatorin addition to its well-known antioxidant activity. In the current study, I review the dosedependenteffects of ascorbate in intracellular signaling pathways of oxidative stress inepilepsy, focusing on its modulation of neuronal survival. I also focus on ascorbic aciddeficiency and treatments in intracellular signaling pathways in the brain as well as indietary requirements, and I discuss the effects of antiepileptic drugs on plasma ascorbatelevels. I conclude with a note on the putative protective role of vitamin C in theneurodegenerative process as well as in epileptic diseases.Corresponding address: Prof. Dr. Mustafa Naziroğlu, Department of Biophysics, Medical Faculty, SüleymanDemirel University, TR-32260, Morfoloji Binasi, Cünür, Isparta, Turkey. Tel: +90 246 2113310; Fax: +90246 2371165; E-mail: mnaziroglu@med.sdu.edu.tr