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

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Prahl A. , Derdowska I. , Dawidowska O. , Neubert K. , Hartrodt B. , Wierzba T. , Juzwa W. , Lammek B.

2002

tom Vol. 76 / nr 10

1433-1439

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.

New Bradykinin Analogues Modified in Position 6 and 7 with Naphthylalanine

100%

Prahl A. , Derdowska I. , Dawidowska O. , Neubert K. , Hartrodt B. , Wierzba T. , Juzwa W. , Lammek B.

tom Vol. 77 / nr 7

881-887

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.

New bradykinin analogues acylated on the N-terminus: effect on rat uterus and blood pressure

100%

Labudda O. , Wierzba T. , Sobolewski D. , Sleszynska M. , Gawinski L. , Plackova M. , Slaninova J. , Prahl A.

tom 54

nr 1

Our previous studies suggested that acylation of the N-terminus of several known B2 antagonists with various kinds of bulky acyl groups consistently improved their antagonistic potency in rat blood pressure assay. On the other hand, our earlier observations also seemed to suggest that the effects of acylation on the contractility of isolated rat uterus depended substantially on the chemical character of the acyl group, as we observed that this modification might either change the range of antagonism or even transform it into agonism. Bearing all this in mind, we decided to synthesize seven new analogues of bradykinin by N-terminal acylation with various acyl groups of a moderately potent B2 antagonist, previously synthesized by Stewart's group, D-Arg-Arg-Pro-Hyp-Gly-Thr-Ser-D-Phe-Thi-Arg. The analogues were tested in vitro for their blood pressure-lowering and uterotonic activities. The modifications either preserved or increased the antagonistic potency in the rat blood pressure test. On the other hand, all seven substituents negatively influenced the interaction with the rat uterine receptors. Our results may be helpful for designing new B2 agonists and antagonists.