IN-VIVO EFFECT OF ALPHA(1)-ACID GLYCOPROTEIN ON EXPERIMENTALLY ENHANCED CAPILLARY-PERMEABILITY IN GUINEA-PIG SKIN

Anaesthetized guinea-pigs were intravenously injected with Evans blue. After intracutaneous injection of agonists (lys-plasminogen, histamin e, platelet-activating factor, thrombin, bradykinin), the resulting wh eals appeared blue in a dose-dependent manner, due to an enhanced capi llary permeability. alpha(1)-Acid glycoprotein, given i.v. in differen t doses (3.125-50 mg/kg) and at different times (30-180 min) before Ev ans blue administration, antagonized the effects of all agonists liste d above. This was shown by a parallel shift of the agonist dose-respon se curves to the right. The effect was time-dependent (t(max): mainly 120 min) and dose-dependent. alpha(1)-Acid glycoprotein antagonized th e agonists in the following order: lys-plasminogen > histamine = plate let-activating factor > thrombin > bradykinin. As all agonists mention ed are suggested to play a major role in the shock-related increase in vascular permeability, a putatively beneficial role of alpha(1)-acid glycoprotein in shock is discussed.