ABSTRACT
This chapter addresses the expression and function of the plasminogen activator system (PAS) in the brain and discusses its connections with the renin-angiotensin (Ang) system. The PAS is primarily responsible for degradation of fibrin and thrombin deposits, thus controlling the extent of blood clot elimination in peripheral tissues. In addition, it is also responsible for the degradation of proteins of the extracellular matrix (ECM) and basement membranes. Plasmin is a broad-spectrum protease predominantly present in the extracellular space. AngII may also influence the activity of the PAS through the regulation of tissue plasminogen activator (tPA) and proteolytic action of urokinase (uPA) expression. AngII directly elevates the uPA and tPA mRNA levels in rat astroglial cells. The chapter shows that both basal and AngII-stimulated levels of PAI-1 mRNA in astroglia of spontaneously hypertensive rat brain are lower than those observed in cultures from normotensive Wistar Kyoto (WKY) animals.
