Neuroserpin is an axonally secreted glycoprotein in the central nervous system (CNS) that belongs to the family of protease inhibitors known as serpins (1,2). Neuroserpin is a serine-protease inhibitor (3) that forms SDS-stable complexes with tissue plasminogen activator (tPA), urokinase and plasmin, but not thrombin (2,4,5). Neuroserpin is expressed in the neocortex, the hippocampal formation, the olfactory bulb and the amygdala in the adult CNS, and it is expressed in the cerebellum, the granule cells and a subgroup of Purkinje cells in the developing embryo (2). tPA expression has been linked to "neuronal plasticity", either in the developing embryo CNS (2,4) or in cases of synpatic remodeling or long-term potentiation (6). Overexpression of tPA may promote neuronal cell death (6). Mutations in the gene which codes for neuroserpin are linked to hereditary dementia (7). Intracerebral administration of neuroserpin after stroke decreases stroke volume and diminishes the apoptotic features of the resulting ischemic penumbra (6).