Bradykinin induces superoxide anion release from human endothelial cells

Abstract

The time-dependent release of superoxide anion (O) from bradykinin (Bk)-stimulated human umbilical vein endothelial cells (EC) was measured as the superoxide dismutase-inhibitable reduction of ferricytochrome C employing a novel application of microspectrophotometry. In the absence of Bk, O release by EC was not detectable. EC exposure to Bk (10⁻⁶ to 10⁻⁵ M) resulted in a rapid release of O. The release of O occurred within 5 minutes of exposure. O release was partially inhibited by indomethacin (63 ± 6%), thus suggesting that arachidonic acid metabolism, through cyclooxygenase, contributes to EC O production. EC O release may be an important component in the pathophysiologic actions of Bk on vascular function.