Toxicology 230 (2007) 164–177 Role of glutathione in determining the differential sensitivity between the cortical and cerebellar regions towards mercury-induced oxidative stress Parvinder Kaur a , Michael Aschner b , Tore Syversen a,∗ a Department of Neuroscience, Norwegian University of Science and Technology, N-7489 Trondheim, Norway b Department of Pediatrics and Pharmacology, and the Kennedy Center, Vanderbilt University Medical Center, B-3307 Medical Center North, 1162 21st Avenue, Nashville, TN 37232-2495, USA Received 5 September 2006; received in revised form 6 November 2006; accepted 9 November 2006 Available online 19 November 2006 Abstract Certain discrete areas of the CNS exhibit enhanced sensitivity towards MeHg. To determine whether GSH is responsible for this particular sensitivity, we investigated its role in MeHg-induced oxidative insult in primary neuronal and astroglial cell cul- tures of both cerebellar and cortical origins. For this purpose, ROS and GSH were measured with the fluorescent indicators, CMH 2 DCFDA and MCB. Cell associated-MeHg was measured with 14 C-radiolabeled MeHg. The intracellular GSH content was modified by pretreatment with NAC or DEM. For each of the dependent variables (ROS, GSH, and MTT), there was an overall significant effect of cellular origin, MeHg and pretreatment in all the cell cultures. A trend towards significant interaction between origin × MeHg × pretreatment was observed only for the dependent variable, ROS (astrocytes p = 0.056; neurons p = 0.000). For GSH, a significant interaction between origin × MeHg was observed only in astrocytes (p = 0.030). The cerebellar cell cultures were more vulnerable (astrocytes mean = 223.77; neurons mean = 138.06) to ROS than the cortical cell cultures (astrocytes mean = 125.18; neurons mean = 107.91) for each of the tested treatments. The cell associated-MeHg increased when treated with DEM, and the cere- bellar cultures varied significantly from the cortical cultures. Non-significant interactions between origin × MeHg × pretreatment for GSH did not explain the significant interactions responsible for the increased amount of ROS produced in these cultures. In summary, although GSH modulation influences MeHg-induced toxicity, the difference in the content of GSH in cortical and cere- bellar cultures fails to account for the increased ROS production in cerebellar cultures. Hence, different approaches for the future studies regarding the mechanisms behind selectivity of MeHg have been discussed. © 2006 Elsevier Ireland Ltd. All rights reserved. Keywords: Neurotoxicity; In vitro; Methylmercury; Glutathione; Reactive oxygen species; Cortical; Cerebellar Abbreviations: MeHg, methylmercury; CNS, central nervous system; GSH, glutathione; ROS, reactive oxygen species; CMH 2 DCFDA, chloro methyl derivative of di-chloro di-hydro fluoresceindiacetate; MCB, monochlorobimane; MTT, [3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide]; NAC, N-acetyl cysteine; DEM, Di-ethyl maleate; FCS, fetal calf serum; DMEM, Dulbecco’s minimum essential medium; HEPES, N-2-hydroxy-ethylpiperazine N ′ -2-ethansulfonic acid; BSA, bovine serum albumin; LSD, least significant difference ∗ Corresponding author at: Department of Neuroscience, Faculty of Medicine, Olav Kyrresgt. 3, N-7489 Trondheim, Norway. Tel.: +47 73598848; fax: +47 73596879. E-mail address: tore.syversen@ntnu.no (T. Syversen). 0300-483X/$ – see front matter © 2006 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.tox.2006.11.058