Effect of bradykinin analogues on the B1 receptor of rat ileum

Abstract The longitudinal muscle of isolated rat ileum is a sensitive bioassay suitable for testing compounds with antagonistic effects on the B 1 receptor. Bradykinin analogues with replacement of proline by alkyl-substituted phenylalanine at position 7 are effective on this receptor as entire molecules and have a stronger antagonistic effect than on the B 2 receptor. A corresponding desArg 9 -compound has a specific effect on the B 1 receptor and a very high antagonistic potency. [LNMPhe 2 ]bradykinin as a compound without any replacement at position 7 or 8 shows antagonistic activity as well.