Neurogenesis following brain ischemia.

Following 5 or 10 min of global ischemia in the adult gerbil there is a tenfold increase in the birth of new cells in the subgranular zone of dentate gyrus of the hippocampus as assessed using BrdU incorporation. This begins at 7 days, peaks at 11 days, and decreases thereafter. Over the next month approximately 25% of the newborn cells disappear. Of the remaining cells, 60% migrate into the granule cell layer where two-thirds become NeuN, calbindin and MAP-2 immunostained neurons. The remaining 40% of the cells migrate into the dentate hilus where 25% of these become GFAP labeled astrocytes. It is proposed that ischemia-induced neurogenesis contributes to the recovery of function, and specifically may serve to improve anterograde and retrograde recent memory function that is lost following global ischemia in animals and man.