Isolation and preliminary biological characterization of KPNFIRFamide, a novel FMRFamide-related peptide from the free-living nematode, Panagrellus redivivus.
A novel FMRFamide-related heptapeptide, Lys-Pro-Asn-Phe-Ile-Arg-Phe-NH2 (KPNFIRFamide), was isolated and characterized from acid ethanol extracts of the free-living nematode, Panagrellus redivivus. Whole-worm extracts contained > or = 9 pmol KPNFIRFamide/g wet weight. A synthetic replicate of this peptide induced a rapid relaxation of tone and inhibited spontaneous contractility in isolated innervated and denervated body-wall muscle strips of the parasitic nematode, Ascaris suum. KPNFIRFamide (0.1 nM) induced measurable relaxations in 50% of the muscle preparations examined. Concentrations > or = 0.3 nM induced relaxation in 100% of muscle preparations examined. The relaxation was short-lived at concentrations of peptide > or = 1 microM and displayed a profile typical of receptor desensitization. These data suggest the occurrence of a closely related peptide in A. suum and add further evidence to the concept of primary structural conservation of FaRPs within the nematodes.
Maule
A G
AG
Comparative Neuroendocrinology Research Group, School of Clinical Medicine, Queen's University of Belfast, Northern Ireland.
Shaw
C
C
Bowman
J W
JW
Halton
D W
DW
Thompson
D P
DP
Thim
L
L
Kubiak
T M
TM
Martin
R A
RA
Geary
T G
TG
D000595:Amino Acid Sequence; D000818:Animals; D019835:FMRFamide; D008969:Molecular Sequence Data; D009132:Muscles / Q000187:drug effects / Q000502:physiology; D009479:Neuropeptides / Q000737:chemistry / Q000145:classification; D018377:Neurotransmitter Agents / Q000302:isolation & purification* / Q000502:physiology; D009842:Oligopeptides / Q000737:chemistry* / Q000494:pharmacology / Q000502:physiology*; D017168:Rhabditida / Q000737:chemistry* / Q000502:physiology
C093065:KPNFIRFamide; D009479:Neuropeptides; D018377:Neurotransmitter Agents; D009842:Oligopeptides; D019835:FMRFamide