DESCRIPTION (provided by applicant): It has been shown in various laboratories that the tissue plasminogen activator (tPA)/plasmin system is critical for excitotoxin-mediated seizures and neurodegeneration in the hippocampus. Upon excitotoxic challenge, tPA activates plasminogen to produce excess plasmin, which then degrades a critical component of the extracellular matrix (ECM), laminin. The loss of the neuron-matrix connection facilitates neuronal death as it does with other cell types. We have found that tPA activity during ethanol treatment and EW is up-regulated in the mouse hippocampus and the amygdala, and that tPA-/- mice are protected from EW-induced seizures and neurodegeneration, as they are from these pathologies induced by excitotoxin injection. Therefore, the mechanism(s) of excitotoxinand EW-induced seizures and neurodegeneration have at least one molecule in common, tPA. To understand better the mechanism of EW-induced seizures and neurodegeneration, we propose to systematically explore the role of tPA in these processes