participates in microsphere embolism-induced microglial activation. (A) Temporal changes in P2X7 receptor expression levels after microsphere embolism induction in rat brain. The results are represented as the mean ± SEM, n = 6 rats. *P <0.05 and **P <0.01 vs. sham rats. (B) Immunohistochemical localization of P2X7- and ED1-positive cells in the microembolic brain. Scale bar = 20 μm. ME, microsphere embolism.