Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8348370 | Peptides | 2014 | 6 Pages |
Abstract
As part of our continuing studies on the structure-activity relationships of cyclic pentapeptides based on the structure of endomorphin-2, we report here the synthesis and biological activities of a new series of analogs incorporating 2â², 3â² or 4â²-methylphenylalanine (MePhe) residues into positions 3 or 4 of the parent cyclopeptide, Dmt-c[d-Lys-Phe-Phe-Asp]NH2 (Dmt = 2â²,6â²-dimethyltyrosine). Analogs with MePhe in position 4 showed a row of magnitude increased μ-opioid receptor (MOP receptor) affinity as compared with a parent compound. The in vitro potencies of the new analogs were determined in calcium mobilization assay performed in Chinese Hamster Ovary (CHO) cells expressing human recombinant opioid receptors and chimeric G proteins. All analogs were strong μ/κ (MOP/KOP) receptor agonists and weak δ (DOP) receptor agonists. In the in vivo hot-plate test in mice, the MePhe4-modified peptides showed remarkable antinociceptive activity after intracerebroventricular (i.c.v.) administration which was most likely due to the concomitant activation of more than one opioid receptor type.
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Authors
Renata Perlikowska, Davide Malfacini, Maria Camilla Cerlesi, Girolamo Calo', Justyna Piekielna, Léonore Floriot, Tiphaine Henry, Jean Claude do-Rego, Csaba Tömböly, Alicja Kluczyk, Anna Janecka,