Structure-activity relationships of neuromedin U. I. Contractile activity of dog neuromedin U-related peptides on isolated chicken crop smooth muscle

Chem Pharm Bull (Tokyo). 1995 Jul;43(7):1148-53. doi: 10.1248/cpb.43.1148.


Synthetic dog neuromedin U-25(d-NMU-25), U-8(d-NMU-8) and their fragments wer examined for contractile activity on chicken crop smooth muscle preparation. The relative activities of d-NMU-25, d-NMU-25(15--25)NH2 and d-NMU-8 to porcine neuromedin U-8 (p-NMU-8) were 1.69, 2.54 and 5.78, respectively. High activity of d-NMU-8 may be attributable to the N-terminal pGlu residue, which provides resistance to aminopeptidases. Various NMU-8 analogs, having various amino acids, N alpha-acetylated amino acids, D-amino acids, or simple organic acids at position 1, were synthesized and evaluated for contractile activity. None of the substitutions caused a significant decrease of the biological activity. Modification at the N-terminal to give aminopeptidase resistance produced analogs with increased contractile activity, presumably because they were not degraded by soluble enzymes released into the bioassay fluid from isolated chicken crop tissue.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Chickens
  • Crop, Avian / drug effects
  • Crop, Avian / physiology
  • Dogs
  • In Vitro Techniques
  • Kinetics
  • Molecular Sequence Data
  • Muscle Contraction / drug effects
  • Muscle, Smooth / drug effects
  • Muscle, Smooth / physiology*
  • Neuropeptides / chemical synthesis*
  • Neuropeptides / metabolism
  • Neuropeptides / pharmacology*
  • Peptide Fragments / chemical synthesis*
  • Peptide Fragments / metabolism
  • Peptide Fragments / pharmacology*
  • Peptide Hydrolases / metabolism
  • Sequence Homology, Amino Acid
  • Swine


  • Neuropeptides
  • Peptide Fragments
  • neuromedin U
  • neuromedin U 8
  • neuromedin U 25
  • Peptide Hydrolases