Relaxations of porcine coronary arteries, following preconstriction with 1 μM U46619, to three consecutive bradykinin doses (0.1 μM; BK1, BK2, BK3), followed by 10 μM quinaprilat, 10 μM omapatrilat, or 1 μM phosphoramidon. Top, original tracing; bottom, mean±s.e.mean of five experiments (data are expressed as a percentage of the contraction induced by U46619).