Dynamic expression of p38beta MAPK in neurons and astrocytes after transient focal ischemia.

Here we report the dynamically regulated expression of p38beta MAPK isoform in specific subsets of cells in postischemic brain. The activity of p38beta MAPK in the postischemic brain revealed biphasic induction at 30 min and 4 days after 1 h MCAO. During the early surge period, p38beta MAPK was preferentially localized in the nucleus and dendrites of neurons in the future infarction area, while during the delayed surge p38beta MAPK was heavily induced in reactive astrocytes in penumbra. The temporally and spatially regulated pattern of p38beta MAPK expression in the postischemic brain suggests distinct roles of p38beta MAPK in neuronal death and in the astrocyte activation.