TY - JOUR T1 - Resveratrol Activation of Nitric Oxide Synthase in Rabbit Brain Synaptosomes: Singlet Oxygen (<sup>1</sup>O<sub>2</sub>) Formation as a Causative Factor of Neurotoxicity JF - In Vivo JO - In Vivo SP - 49 LP - 53 VL - 24 IS - 1 AU - STELIOS FOTIOU AU - DESPINA FOTIOU AU - ANASTASIA ALAMANOU AU - GEORGE DELICONSTANTINOS Y1 - 2010/01/01 UR - http://iv.iiarjournals.org/content/24/1/49.abstract N2 - In the present study it was shown that resveratrol (3,4,5-trihydroxystilbene), an efficient light-absorbing molecule, during its transition from trans to cis configuration under UV light, transfers its energy of excitation to triplet oxygen to produce singlet oxygen (1O2). This transition is prevented by Trolox, a quencher of singlet oxygen. In the presence of a stable amount of nitrosoglutathione, UV-irradiated resveratrol reacts with nitric oxide (NO) originating from the nitrosoglutathione to produce peroxynitrite (ONOO−). Beta-carotene, acting as a quencher of 1O2, prevents the transition of resveratrol from trans to cis. Beta-carotene also prevents DNA damage induced by the 1O2. NO synthase (NOS) activity in synaptosomes isolated from rabbit brain increased approximately three-fold by resveratrol and the NO released was converted to ONOO−. Resveratrol increased the lipid fluidity of synaptosomal plasma membranes. These changes suggest that the incorporation of resveratrol into synaptosomal plasma membranes causes an up-regulation of NO synthase. On the other hand, the simultaneous ONOO− and 1O2 formation may cause disturbances in transmembrane signal transduction leading to neurotoxicity. The present study concerning the behavior of resveratrol with respect to its structure and potential prooxidant-antioxidant function provides important new clues as to the role of this fascinating molecule in pathophysiology. Copyright © 2010 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved ER -