The last decade has seen a dramatic explosion in the studies of thrombogenesis and fibrinolysis. These processes involve cascades of enzymes acting on precursor zymogens, thus allowing for multi-level, post-translational regulation. Regulation also occurs at the transciptional and translational levels and in the precise bonds which these proteolytic enzymes recognize and cleave. Post-translational regulation also occurs by specific inhibitors, the serpins, with precise active sites, regulated by hormones, modulators, and other molecules. Cell surface receptors for thrombin and the plasminogen activators (PAs) have been found, allowing for another dimension for regulation. Roles for these molecules in cell migration and tissue remodelling are expanding. In metastasis, inflammation and physiological processes such as ovulation, proteases and inhibitors are being actively studied. Recent information suggests important roles in the nervous systems. At this time, it is necessary to bring leaders in this emerging field together to communicate the still nascent state of knowledge about such intriguing molecules in the development, maintenance, plasticity and degeneration of the nervous system. The key for this advanced research workshop is the term "extravascular." These molecules are gene products of neuron and glia cells. The evidence on which this workshop is based is four-fold: (1) presence and release of urokinase (uPA) and tissue PA (tPA) at tips of nerve growth cones, (2) identity of glia-derived nexin and protease nexin (PNI), (3) localization of PNI at neuromuscular synapses, (4) detection of serpin and Kunitz inhibitor sequences in B-amyloid cloned from neuritic plaques of victims of Alzheimer's disease.
