Perfused prenodal lymphatics are constricted by prostaglandins

Prostaglandins may contribute to the control of lymph flow by affecting lymphatic vessel contractility. We measured the pressure in perfused prenodal lymphatic vessel in the paw of the anesthetized dog as affected by administration of prostaglandins E1, E2, F2 alpha or arachidonic acid. The forelimb was perfused at constant flow with blood obtained from a femoral artery. Systemic arterial, central venous, and forelimb vascular pressures were measured. When added to the lymphatic perfusate, all of the prostaglandins and arachidonic acid caused constriction of lymphatic vessels. Perfusion of prenodal lymphatics separated from downstream nodes and vessels showed that this constriction occurred primarily in prenodal vessels. However, only prostaglandin F2 alpha caused lymphatic constriction when infused into the blood to the forelimb. Because prostaglandins are a common component of the lymph leaving an area of tissue damage, these results are compatible with the possibility that prostaglandins, by directly affecting lymphatics, help modulate lymph flow following local injury.