title: Isolation and preliminary biological characterization of KPNFIRFamide, a novel FMRFamide-related peptide from the free-living nematode, Panagrellus redivivus.
abstract: 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.
authors.affiliation: Comparative Neuroendocrinology Research Group, School of Clinical Medicine, Queen's University of Belfast, Northern Ireland.
authors.forename: A G
authors.initials: AG
authors.lastname: Maule
authors.forename: C
authors.initials: C
authors.lastname: Shaw
authors.forename: J W
authors.initials: JW
authors.lastname: Bowman
authors.forename: D W
authors.initials: DW
authors.lastname: Halton
authors.forename: D P
authors.initials: DP
authors.lastname: Thompson
authors.forename: L
authors.initials: L
authors.lastname: Thim
authors.forename: T M
authors.initials: TM
authors.lastname: Kubiak
authors.forename: R A
authors.initials: RA
authors.lastname: Martin
authors.forename: T G
authors.initials: TG
authors.lastname: Geary
mesh_terms: 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
chemical_list: C093065:KPNFIRFamide; D009479:Neuropeptides; D018377:Neurotransmitter Agents; D009842:Oligopeptides; D019835:FMRFamide