Changes in the mRNA and protein expression of P2X
receptors in the striatum and substantia nigra obtained from P2X
receptor wild-type (WT) and P2X
-/- (KO) mice after in vivo MPTP treatment. Mice (6-8 mice per group) were injected i.p. with 4 × 20 mg/kg of MPTP or saline (SAL). A-C. After decapitation, the brains were removed immediately, total RNA extracted from the striatum (A, C) and substantia nigra (B) and then reverse-transcribed to cDNA. Data are displayed as the means ± S.E.M. Asterisks indicate significant differences from the corresponding saline-injected mice or between genotypes as indicated (*P < 0.05, ***P < 0.0001). D, E. and F. Immunofluorescent staining for P2X7 receptor and microglial cells in striatal sections of saline- and MPTP-treated WT and P2X7-/- mice. Merged pictures. Fluorescein-labeled GSL I - isolectin B4 is a marker for endothelial (see stars in picture "F") and microglial cells. P2X7 receptors were labeled with a P2X7-DyLight 549 conjugate (red). Orange means the same localization for both stains. DAPI (in Vectashield mounting medium) labels nuclei (blue). Scale bar: 20 μm. D. Detail of the striatal section of saline-treated WT mouse brain. Inserts (arrows) show the localization of P2X7 receptors in FITC-labeled microglial cells. E. Only microglial cells are labeled (green, insert, arrow) in the striatal section of MPTP-treated WT mouse brain. F. Microglia (arrow, insert) and endothelial cells (stars) are labeled by the isolectin, but no P2X7 immunofluorescence is visible in the striatal sections of saline-treated P2X7-/- mouse brain.