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EN
The present work is a part of our studies aimed at clarifying the influence of sterical constraints in N-terminal part of AVP analogues on the pharmacological activity of the resulting peptides. In this study we described the synthesis of four new analogues of AVP substituted at positions 2 and 3 or 3 and 4 with two diastereoisomers of 4-aminopyroglutamic acid and four peptides in which we combined the above modification with the placement of 3-mercaptopropionic acid at position 1. All new peptides were not active in bioassays for pressor, antidiuretic and uterotonic activity.
EN
We describe 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 Ser6 with L-1- and L-2-naphthylalanine. In two further analogues this modification was combined with placement in position 7 of D-naphthylalanine residue. We also 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 modifications proposed decreased significantly the B2 antagonistic activity. Moreover, our earlier observation, suggesting that acylation of the N-terminus of many BK antagonists with bulky groups consistently improved the antagonistic potency, appears to be valid only for one pair of analogues.
EN
Four new analogues of a previously designed bradykinin antagonist, D-Arg-Arg-Pro- -Hyp-Gly-Thi-Ser-D-Phe-Thi-Arg, containing replacements in positions 6 and 7 with all possible combinations of enantiomers of N-methylphenylalanine (MePhe) were designed, synthesized and bioassayed. The presence of two consecutive MePhe residues in the sequence of the analogues caused great difficulties in the synthesis. The best results for the CO-N(CH3) bond formation were obtained using O-(7-azabenzotriazol-1-yl)-1,1,3,3- -tetramethyluronium hexafluorophosphate/7-azabenzotriazol-1-ol (HATU/HOAt) as coupling reagent (Fmoc strategy). The antagonistic potency of these peptides was assessed by their ability to inhibit vasodepressor response to exogenous bradykinin in conscious rats. Our results showed that the modifications proposed resulted in a decrease in antagonistic activity. However, we demonstrated once again that the D-amino acid in position 7 ofBKantagonists may be replaced by a suitable L-amino acid residue. Our results may be of value in the design of new B2-antagonists.
EN
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.
EN
The synthesis and some pharmacological properties of five new analogues of arginine vasopressin (AVP) substituted with N-benzylglycine are described. All new peptides were tested for pressor and uterotonic activity. The results obtained imply that the structural change studied is in general incompatible with interaction of the analogues withV1A and OT receptors, however, in combination with suitable additional changes, may be of value in the design of new antagonists of these receptors.
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