Structure-Activity Relationships of Rat Neuromedin U for Smooth Muscle Contraction.

Abstract

Rat neuromedin U (r-NMU) and its fragment peptide amides were synthesized by solid-phase methodology. Using a chicken crop smooth muscle contraction assay, the potency of r-NMU and its fragments relative to porcine neuromedin U-8 (p-NMU-8) was r-NMU: 10.25 +/- 2.88, r-NMU (6-23): 8.01 +/- 1.04, r-NMU (10-23): 2.76 +/- 0.46, r-NMU (13-23): 2.81 +/- 0.52, and r-NMU (16-23): 0.88 +/- 0.19, respectively. Two heptapeptides, r-NMU (17-23) and r-NMU (16-22), had a relative potency of 0.61 and 0.03 respectively, and elicited maximal contraction at a dose of 10 microM to a similar degree to p-NMU-8. The other shorter C-terminal fragments did not elicit the maximal contraction or any activity. In a rat uterus contraction assay, r-NMU (13-23), but not r-NMU (16-23), at a dose of 4 nM retained as high a stimulatory activity as r-NMU itself. r-NMU (17-22) was the smallest peptide fragment to elicit the maximal sustained contraction at 10 microM. These results indicate that the amino acid sequence Phe-Leu-Phe-Arg-Pro-Arg, corresponding to positions 17 to 22 of r-NMU, may be essential for contractile activity. N-terminal peptide segments Tyr-Gln-Gly-Pro corresponding to positions 6 to 9, and Ser-Gly-Gly corresponding to positions 13 to 15, appear to be of special importance for potent activity.

Structure-Activity Relationships of Neuromedin U. V. Study on the Stability of Porcine Neuromedin U-8 at the C-Terminal Asparagine Amide under Mild Alkaline and Acidic Conditions

“…The same result was obtained for rat neuromedin U-23, 5,14,15) dog neuromedin U-8 bearing pGlu at the N-terminal, 6,16) and [Gly 1 ]-neuromedin U-8, 17) (data not shown). The displacement curves of synthetic N-terminally deleted analogs 5) such as H-Phe-LeuPhe-Arg-Pro-Arg-Asn-NH 2 , H-Leu-Phe-Arg-Pro-Arg-Asn-NH 2 , and H-Phe-Arg-Pro-Arg-Asn-NH 2 showed reduced but considerable cross-reactivity. The C-terminally deleted analogs H-Tyr-Phe-Leu-Phe-Arg-Pro-Arg-OH 6) and [Gly 8 ]-neuromedin U-8 17) showed no activity in displacing the tracer.…”

“…5) The amino acid analysis data of various synthetic peptides is shown in Table 1, while their FAB-MS analysis data and characteristics are shown in Table 2.…”

Identification of non-peptidic neuromedin U receptor modulators by a robust homogeneous screening assay

“…It is known that these structurally highly conserved neuropeptides share a motif of FLFRPRX-amide, suggesting the importance of this sequence in the interaction with its cognate receptors. Specifically, NMU-8 peptides precede with a large flexibility of the 4 amino acids sequence rich in hydrophobic residues, namely Tyr -NH 2 in all species, implying that an amphiphilic structure could be designed [23][24][25][26][27][28][29] . Diphenyl groups are widely present in many drugs on the market targeting GPCR, including adrenergic receptor antagonists, muscarinic receptor antagonists, analgesic agents (opioid receptor agonists), anti-allergic medications (histamine receptor-1 antagonists), and serotonin receptor modulators [34] .…”

“…Structural modifications Five groups of analogs to 101586 were designed and synthesized. Compounds 1a-d were designed based on the SAR information relative to porcine NMU-8 [23][24][25][26][27][28][29] . The diphenyl group was introduced to resemble the hydrophobic residues in this peptide, as we believe this group may bind to a hydrophobic site on the hNMU-R, and that an interaction with an anionic site of the receptor might be realized by linking to a cyclized guanidine group with changes in the carbon chain length and ring size.…”

Localisation of NMU1R and NMU2R in human and rat central nervous system and effects of neuromedin-U following central administration in rats

“…Neuromedin-U (NmU) was originally isolated from porcine spinal cord by Minamino et al (1985) and was subsequently isolated from a variety of species including rat (NmU-23), human (NmU-25) and frog (NmU-25) (Conlon et al 1988;Domin et al 1989;O'Harte et al 1991). The core active sequence (Phe-LeuPhe-Arg-Pro-Arg-Asn-NH2) lies between residues 2 and 8 and is common to mammalian species Sakura et al 1991).…”