Glutamate Receptors Editing Figure 10. KA-induced editing of AMPA and KA glutamate receptor subunits in the cortex of COX-2+/+ and COX-22/2 mice. RNA editing levels of AMPA and KA glutamate receptors in the cerebral cortex of mice exposed to acute KA-injection. (A) GluR3 R/G site flip- flop-variant and (B) GluR6 I/V, Y/C and Q/R editing site. Data are presented as mean 6 SEM (n = 6). Statistical analysis was performed with Student’s t test (*P,0.05, **P,0.01, ***P,0.001). doi:10.1371/journal.pone.0019398.g010 p,0.05) when compared to vehicle-injected COX-22/2 mice. No changes were observed in the mRNA expression of CD11b (Fig. 12E–F). No change was observed in the mRNA expression of iNOS, a major source or oxidative stress, when we compared vehicle- injected COX-22/2 with vehicle-injected WT mice in the hippocampus or cortex (Fig. 11G, Fig. 12G). In the hippocampus, COX-22/2 mice (2.1960.22, p,0.001) showed a higher increase in iNOS mRNA levels in response to KA compared to WT mice (1.6160.14, p,0.01). Also, KA-injected COX-22/2 mice showed an increase in the expression of iNOS (1.3660.15, p,0.05) when compared with KA-injected WT mice (Fig. 11G). In the cortex, no changes were observed in the expression of iNOS in any of the groups (Fig. 12G). Furthermore, we analyzed the mRNA expression of the pro- inflammatory transcription factor NF-kB. In the hippocampus, an increase in the mRNA levels of NF-kB was observed in KA- injected compared to vehicle-injected COX-22/2 mice (1.2060.05, p,0.001) (Fig. 11D). KA-injected COX-22/2 mice showed an increase in the expression of NF-kB (1.1960.06, p,0.01) when compared with KA-injected WT mice (Fig. 11D). In the cortex, no changes were observed in the expression of NF- kB in any of the groups analyzed (Fig. 12G). Next, we examined mRNA gene expression of MAP-2 that belongs to the microtubule-associated protein family, which is enriched in neuronal cell bodies and dendrites. In the hippocam- pus, KA-injection significantly increased the expression of MAP-2 (1.4360.09, p,0.01) in COX-22/2 mice (Fig. 11H). In the cortex, no change was observed in MAP-2 gene expression (Fig. 12H). The mRNA expression of COX-1 was not significantly changed in either COX-22/2 and WT mice after KA exposure in either brain areas (data not shown), indicating that the increased neuroinflammatory response was not due to an increased compensatory expression of COX-1 in response to KA as a consequence of COX-2 gene deletion. Discussion In this study, we report for the first time a complete analysis of mRNA expression for all subunits of AMPA (GluR1–4), KA (GluR5–7, KA1 and KA2) and NMDA (NR1, NR2a–b and NR3a–b) receptors in the hippocampus and cortex from COX- 22/2 and WT mice after KA injection. We used KA as a model of excitotoxicity because of its strong and well-characterized time and regional effects in inducing seizures and subsequent neuronal damage. Administration of KA has been shown to increase PLoS ONE | www.plosone.org 14 May 2011 | Volume 6 | Issue 5 | e19398