THE EFFECT OF NITRIC-OXIDE DONORS ON THE RELEASE OF PLASMINOGEN-ACTIVATOR INHIBITOR (PAI) FROM RABBIT PLATELETS IN-VITRO

Here we describe effects of four nitric oxide (NO) donors, 4-arylsubst ituted oxatriazol derivatives and 3-morpholino-sydnonimine (SIN-1) at concentrations of 30-1000 mu M on the release of plasminogen activator inhibitor (PAI) from rabbit platelets in vitro. At 37 degrees C, pH o f 7.4 and a concentration of 30 mu M, all compounds released NO as mea sured by the Werringloer's technique. The NO-generating potency of the compounds correlated with their capacity to inhibit the release of PA I from platelets and both phenomena were concentration-dependent. We c onclude that various types of NO-donors activate plasma fibrinolytic s ystem through inhibition of the release of PAI from platelets.