PLAU and brain ischemia: However, recent research with in vitro models of hypoxia, in vivo models of cerebral ischemia and different neuroradiological techniques has revealed that during the recovery phase from a hypoxic injury neurons release the serine proteinase urokinase-type plasminogen activator (uPA) and astrocytes recruit its receptor (uPAR) to their plasma membrane; and that binding of neuronal uPA to astrocytic uPAR promotes the recovery of the “tripartite synapse” that has suffered an acute ischemic injury.