Abstract
Glial cells and neurons show a different spatiotemporal excitability, and distinctively regulate brain functions. Glial cells, especially astrocytes, have very thin and fine processes, by which they communicate with neurons and glial cells. Due to such thin structure, the function of these fine processes could not be detected. Shigetomi et al. discovered membrane - associated Ca2+ probes, i. e. , Lck - GCaMP3, and visualized Ca2+ excitability there. Using this Ca2+ probes, we found that ischemic tolerance is dependent on astrocytic excitability. Ischemic tolerance is well - known event, by which the brain acquires resistance against brain ischemia. Due to its strong brain protective actions, there have been many lines of literature about ischemic tolerance. However, almost all such researches just focused on neurons. Preconditioning (PC) enhanced Ca2+ excitability in astrocytes, which could be obser ved only when we used the new Ca2+ indicator. PC upregulated P2X7 receptor, one of ATP receptor/channel, in astrocytes, and the astrocytic P2X7 receptor could function as a switch and/or trigger for formation of astrocyte- mediated ischemic tolerance.
