The interrelationship among bradykinin, various vasoactive substances, and macromolecular permeability in the canine forelimb

Abstract

Bradykinin (0.8 μg base/min) infused locally intraarterially into canine forelimbs perfused at constant inflow causes marked increases in lymph flow rate and lymph total protein concentration. This same dose of bradykinin infused locally intraarterially for 60 min into forelimbs perfused at constant inflow with vasopressin (0.8 P.U./min) or serotonin (15 μg base/min) or following a large intravenous bolus injection of methylprednisolone fails to increase lymph flow rate and lymph total protein concentration relative to control. When this dose of bradykinin is infused locally intraarterially for 60 min with papaverine (0.4 mg/min) or methylprednisolone (50 μg/min) lymph flow rate and lymph total protein concentration are markedly increased. The antagonism of the bradykinin-induced increase in protein efflux by vasopressin, serotonin, and methylprednisolone is independent of changes in blood flow, vascular pressures, or perfused surface area. Thus, some but not all vasoactive agents possess the unique ability to prevent the increase in protein efflux by bradykinin.