Endothelium dependent relaxation of human corpus cavernosum by bradykinin

The release of endothelium-derived relaxing factor (EDRF) from human corpus cavernosum (CC) tissue was confirmed by demonstrating that bradykinin produces endothelium dependent relaxation of human CC tissue. Human CC strips were set in a tissue bath and isometric tension changes were recorded. All strips showed spontaneous contractions and produced tonic contractions by both high potassium solution and noradrenaline (NA) (10(-9) to 10(-4) M) in a dose dependent manner. In preparations precontracted with NA, relaxation was produced by bradykinin (10(-7) to 2 x 10(-6) M). Strips lacking endothelium were contracted by NA but no relaxation was observed with the addition of bradykinin. More direct evidence of the release of EDRF from human CC was demonstrated by a "sandwich" mount. We conclude that bradykinin relaxes human CC by releasing EDRF and that this EDRF may be a factor in erectile function.