New Analogues of Bradykinin Substituted in the C-Terminal Part of the Molecule with Naphthylalanine

This paper describes the synthesis and some pharmacological properties of eight new analogues of a previously synthesized bradykinin antagonist, D-Arg-Arg-Pro-Hyp-Gly- Thi-Ser-D-Phe-Thi-Arg. Two peptides were designed by substitution of Thi8 with L-1- and L-2-naphthylalanine. In two further analogues this modification was combined with placement in position 7 of D-2-naphthylalanine residue. Finally, we obtained four analogues by acylation of N-terminus of the peptides mentioned above with 1-adamantaneacetic acid. The activity of analogues was assessed by their ability to inhibit vasodepressor response to exogenous bradykinin (rat blood pressure test). Our results indicate that the modification proposed decreased the B2 antagonistic activity, however, the range of this effect was different. We also observed that even minor changes in the structure of the C-terminal part of the B2 antagonists may significantly influence their activity.