Implications for the Epilepsy Seen in the Dementia FENIB

Chronic ethanol abuse causes upregulation of N-methyl-D-aspartate (NMDA) receptors, which underlies seizures and brain damage on ethanol withdrawal (EW). Here we show that tissue plasminogen activator (tPA), a protease implicated in neuronal plasticity and seizures, is induced in the limbic system by chronic ethanol consumption, tem-porally coinciding with upregulation of NMDA receptors. tPA interacts with NR2B-containing NMDA receptors and is required for upregulation of the NR2B subunit in re-sponse to ethanol. As a consequence, tPA-deficient mice have reduced NR2B, extracellular signal-regulated kinase 1/2 phosphorylation, and seizures after EW. tPA-mediated facilitation of EW seizures is abolished by NR2B-specific NMDA antagonist ifenprodil. These results indicate that tPA mediates the development of physical dependence on ethanol by regulating NR2B-containing NMDA receptors