In Vitro Membrane Permeation Studies and in Vivo Antinociception of Glycosylated Dmt(1)-DALDA Analogues

• Published in: ACS medicinal chemistry letters Vol. 5; no. 4; pp. 352 - 357
• Main Authors: Ballet, Steven, Betti, Cecilia, Novoa, Alexandre, Toemboely, Csaba, Nielsen, Carsten Uhd, Helms, Hans Christian, Lesniak, Anna, Kleczkowska, Patrycja, Chung, Nga N., Lipkowski, Andrzej W., Brodin, Birger, Tourwe, Dirk, Schiller, Peter W.
• Format: Journal Article
• Language: English
• Published: WASHINGTON Amer Chemical Soc 10.04.2014
• Subjects: Chemistry, Medicinal; Life Sciences & Biomedicine; Pharmacology & Pharmacy; Science & Technology; OPIOID ACTIVITY; TRANSPORT; PERMEABILITY; in vivo antinociception; Opioid peptides; glycosylation; MANNITOL; Dmt-DALDA; BLOOD-BRAIN-BARRIER; BIOAVAILABILITY
• DOI: 10.1021/ml4004765
• ISSN: 1948-5875

In this study the mu opioid receptor (MOR) ligands DALDA (Tyr-D-Arg-Phe-Lys-NH2) and Dmt(1)-DALDA (Dmt-D-Arg-Phe-Lys-NH2, Dmt = 2',6'-dimethyltyrosine) were glycosylated at the N- or C-terminus. Subsequently, the modified peptides were subjected to in vitro and in vivo evaluation. In contrast to the N-terminally modified peptide (3), all peptide analogues derivatized at the C-terminus (4-7) proved to possess high affinity and agonist potency at both MOR and DOR (delta opioid receptor). Results of the Caco-2 monolayer permeation, as well as in vitro blood-brain barrier model experiments, showed that, in the case of compound 4, the glycosylation only slightly diminished the lumen-to-blood and blood-to-lumen transport. Altogether, these experiments were indicative of transcellular transport but not active transport. In vivo assays demonstrated that the peptides were capable of (i) crossing the blood-brain barrier (BBB) and (ii) activating both the spinal ascending as well as the descending opioid pathways, as determined by the tail-flick and hot-plate assays, respectively. In contrast to the highly selective MOR agonist Dmt(1)-DALDA 1, compounds 4-7 are mixed MOR/DOR agonists, expected to produce reduced opioid-related side effects.