[en] Substance P, neurokinin A, neurokinin B, and N-acylated pentapeptide X-Phe-Phe-Gly-Leu-Met-NH2 analogs of substance P7-11 were tested for their spasmogenic activities in intact or in epithelium-denuded tracheal strips from guinea pig. Epithelium removal enhanced the efficacies and potencies relative to substance P of all the peptides tested in guinea pig trachea. In epithelium-containing preparations, the presence of a cyclic substituent (o-hydroxyphenyl-acetyl, p-hydroxyphenyl-acetyl, pyroglutamyl) in Phe7 greatly enhanced the potency and efficacy compared to substance P. These substitutions were twice as active as neurokinin A itself. The presence of an aliphatic chain (non-protected and t-butyloxycarbonyl-protected aminopropyl and aminocaproyl) in Phe7 also improved the potency and the efficacy of the synthetic peptides. The aliphatic substituents could favour an increase in local concentration of the peptides in the vicinity of the receptor(s) allowing a more effective ligand-receptor interaction. Thus, lipophilicity could be determinant in the potency of the peptides in intact guinea pig trachea. In epithelium-denuded tracheal strips from guinea pig, all the synthetic peptides were more effective than substance P but less active than neurokinin A which probably reflects the presence of the NK2 receptor subtype, which may be predominant in this type of epithelium-denuded preparation. Our results suggest that hydrophobicity plays a strong role in the interaction of the peptides, namely substance P and its analogues with the membrane and possibly the receptors themselves.
Disciplines :
Biochemistry, biophysics & molecular biology
Identifiers :
UNILU:UL-ARTICLE-2008-222
Author, co-author :
Tschirhart, Eric ; University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Life Science Research Unit
Schmitt, P.
Bertrand, C.
Mayer, M.
Magneney, S.
Landry, Y.
Michelot, R.
Language :
English
Title :
Contractile activity of the N-acylated C-terminal part of substance P7-11 in guinea pig trachea. Effect of epithelium removal
Publication date :
1989
Journal title :
Naunyn-Schmiedeberg's Archives of Pharmacology
ISSN :
0028-1298
Publisher :
Springer Science & Business Media B.V., New York, United States - New York