AUTORADIOGRAPHIC VISUALIZATION OF B1 BRADYKININ RECEPTORS IN PORCINE VASCULAR TISSUES IN THE PRESENCE OR ABSENCE OF INFLAMMATION

B1 bradykinin receptors were visualized by using the B1 bradykinin rec eptor agonist [H-3]des-Ar-10-kallidin in receptor autoradiography expe riments. Cryosections were prepared from arterial vessels from a healt hy control pig, a pig with pre-existing inflammation and an animal wit h experimental sepsis induced by an infusion of bacterial lipopolysacc haride (LPS). Only diffusely scattered silver grains with no preferenc e for a distinct tissue structure were detected on emulsion-coated cov erslips above the cryosections from the healthy control animal. This i ndicates that under normal circumstances no or only minute amounts of B1 bradykinin receptors are present in these tissues. In contrast, a 3 -fold increase in specific B1 bradykinin receptor binding was observed on both the corresponding preparations of the sick piglet and of that with experimentally induced sepsis. A similar enhancement of specific [H-3]des-Arg(10)-kallidin binding occurred in preparations devoid of endothelium. By comparison with the stained cryosection on the slide t he silver grains showed a preferential distribution above smooth muscl e cells. Taken together our data are consistent with the hypothesis th at B1 bradykinin receptors are induced in the muscle layer of large ve ssels not only after experimentally-induced sepsis but also in pre-exi sting inflammatory disease.