Cortical Amino Acid Release Figure 6. Effect of the Ca2+ channel blocker Cd2+ on hypoosmotic medium-induced amino acid release in the cortex. (a–c) Microdialysis probes were perfused with hypoosmotic medium (HYPO) in the presence or absence of 300 mM Cd2+ given 20 minutes prior to and during one-hour hypoosmotic medium perfusion. Each rat had two microdialysis probes implanted on opposite sides of the cortex (one perfused with HYPO alone and the other with HYPO+Cd2+). The data represent the average dialysate levels 6SEM of glutamate (a), aspartate (b), and taurine (c) from 5 rats. doi:10.1371/journal.pone.0003543.g006 Figure 7. Effect of the glutamate transporter inhibitor DL-TBOA on hypoosmotic medium induced amino acid release in the cortex and glutamate transporter reversal in cultured astrocytes. (a–b) Microdialysis probes implanted on opposite sides of the cortex were perfused with hypoosmotic medium in the presence or absence of 500 mM DL-TBOA, given 20 minutes prior to and during one hour hypoosmotic medium perfusion. The data represent average dialysate levels of glutamate (a), aspartate (b) 6SEM from 4 rats. ** p,0.01 HYPO vs. HYPO+TBOA. (c) DL-TBOA effectively prevented reversal of glutamate transporter in cultured astrocytes. Cultured astrocytes were superfused for one hour with 1 mM ouabain and additionally for 20 min high [KCl] (100 mM) plus ouabain to induce glutamate transporter reversal. 300 mM DL-TBOA was given 10 minutes prior to and during the high [KCl] perfusion in the presence of ouabain. The data are the average values 6SEM for three experiments in each group. ** p,0.01 KCl vs. KCl+TBOA. doi:10.1371/journal.pone.0003543.g007 Figure 8. Effect of H2O2 on hypoosmotic medium induced amino acid release in the cortex. (a–c) Two microdialysis probes implanted on opposite sides of the cortex were perfused with hypoosmotic medium in the presence or absence of 1 mM H2O2 given 20 minutes prior to and during one-hour hypoosmotic medium perfusion. The data represent the average dialysate levels 6SEM of glutamate (a), aspartate (b) and taurine (c) from 9 rats. ** p,0.01 HYPO vs. HYPO+H2O2. In separate experiments, rats were perfused with 1 mM H2O2 alone (N = 5). doi:10.1371/journal.pone.0003543.g008 PLoS ONE | www.plosone.org 8 October 2008 | Volume 3 | Issue 10 | e3543