The roles of P2X7 receptor in regional-specific microglial responses in the rat brain following status epilepticus

Recently, we have reported that astroglial activations in response to status epilepticus (SE) show regional-specific manners in the rat hippocampus. However, it is unknown that microglial responses to SE would show regional-specific patterns. Therefore, the present study was designed to elucidate the regional-specific microglial activation and relationship between P2X7 receptor functions and SE-induced microglial responses in the rat brain. Following SE, microglia appeared amoeboid or phagocytic in the dentate gyrus and the piriform cortex. In contrast, elongated microglia were observed in the CA1 hippocampal regions and the frontoparietal cortex. In the dentate gyrus, the CA1 hippocampal regions, and the frontoparietal cortex, these microglial activation accelerated by BzATP (a P2X7 receptor agonist)-infusion, but inhibited by OxATP (a P2X7 receptor antagonist). However, SE-induced microglial activation in the piriform cortex was not affected by BzATP or OxATP-infusion. Therefore, our findings indicate that SE-induced microglial activation may show regional-specific manners, and suggest that P2X7 receptor function differently modulates SE-induced microglial responses in distinct brain regions.