Analogues of F8Famide resistant to degradation, with high affinity and in vivo effects.
Four analogues of Phe-Leu-Phe-Gln-Pro-Gln-Arg-Phe-NH2, a mammalian FMRFamide-like peptide with antiopiate properties, were synthesized with N-terminus modifications and were shown to have high affinity for F8Famide binding sites. The degradation rate of these analogues in mouse brain slices was 3 times lower than that of the natural peptide. One analogue, (2DME)Y8Fa (D.Tyr-D.Leu-[N-Me]Phe-Gln-Pro-Gln-Arg-Phe-NH2), produced a clear hyperalgic effect and inhibited morphine analgesia in the mouse tail-flick test at lower doses than did the parent compound. (3D)Y8Fa (D.Tyr-D.Leu-D.Phe-Gln-Pro-Gln-Arg-Phe-NH2) and (2D)Y8Fa (D.Tyr-D.Leu-Phe-Gln-Pro-Gln-Arg-Phe-NH2) in contrast did not decrease morphine analgesia but were analgesic alone. The analgesic effects of 22 nmol (2D)Y8Fa and (3D)Y8Fa were decreased by (1DME)Y8Fa (D.Tyr-Leu-[N-Me]Phe-Gln-Pro-Gln-Arg-Phe-NH2) or (2DME)Y8Fa and were reversed by naloxone. These results indicate opioid modulating properties of F8Famide. These analogues may prove to be useful tools for studying the modulation of pain by F8Famide.
Gicquel
S
S
Laboratoire de Pharmacologie et de Toxicologie Fondamentales, CNRS, Toulouse, France.
Mazarguil
H
H
Allard
M
M
Simonnet
G
G
Zajac
J M
JM
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D008566:Membranes / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D009020:Morphine / Q000037:antagonists & inhibitors / Q000494:pharmacology; D009842:Oligopeptides / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D011930:Reaction Time / Q000187:drug effects
D009842:Oligopeptides; D009020:Morphine; C053651:phenylalanyl-leucyl-phenylalanyl-glutaminyl-prolyl-glutaminyl-arginyl-phenylalaninamide