title: Identification of a novel frog RFamide and its effect on the latency of the tail-flick response of the newt.
abstract: Neuropeptide FF, one of the mammalian PQRFamides, has been reported to affect the latency of the tail-flick response in rat. We intended to examine the nociceptive effect by the peptide PQRFamides from the comparative aspect. Using the dot immunoblot method with antiserum to FMRFamide as an assay system, a peptide (frog's nociception-related peptide, fNRP) which has the C-terminal sequence PQRFamide was isolated from the brain of the frog, Rana catesbeiana. The determined sequence, SIPNLPQRF-NH(2), is the same as that named first (frog growth hormone-releasing peptide-gene-related peptide-1: fGRP-RP-1, which is encoded in the cDNA of the fGRP precursor. Since the peptide was isolated from the frog brain, we tested another amphibian, the newt, which has a tail, by the hot beam tail-flick test. Intraperitoneal injection of fNRP significantly increased the latency of the pain response (tail-flick) 90 min after administration. The effect was blocked by simultaneous administration of 5 mM naloxone. The result provides evidence for the interaction of fNRP and opioid steps in the analgesia pathways in the newt.
authors.affiliation: Department of Biological Science, Faculty of Life and Environmental Science, Shimane-University, 1060 Nishikawatsu-cho, Matsue 690-8504, Japan.
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Kanetoh
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Sugikawa
authors.forename: Itaru
authors.initials: I
authors.lastname: Sasaki
authors.forename: Yojiro
authors.initials: Y
authors.lastname: Muneoka
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Minakata
authors.forename: Ikuo
authors.initials: I
authors.lastname: Takabatake
authors.forename: Masaaki
authors.initials: M
authors.lastname: Fujimoto
mesh_terms: D000818:Animals; D001681:Biological Assay; D001923:Brain Chemistry; D002851:Chromatography, High Pressure Liquid; D004336:Drug Antagonism; D006358:Hot Temperature; D015151:Immunoblotting / Q000379:methods; D009270:Naloxone / Q000494:pharmacology; D036103:Nanotechnology; D009479:Neuropeptides / Q000276:immunology / Q000302:isolation & purification / Q000494:pharmacology*; D010147:Pain Measurement / Q000187:drug effects*; D011892:Rana catesbeiana; D011930:Reaction Time / Q000187:drug effects* / Q000502:physiology; D012455:Salamandridae; D020539:Sequence Analysis, Protein; D021241:Spectrometry, Mass, Electrospray Ionization; D013623:Tail / Q000187:drug effects / Q000503:physiopathology / Q000528:radiation effects; D014020:Tissue Extracts / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D009479:Neuropeptides; D014020:Tissue Extracts; C058047:arginylphenylalaninamide; D009270:Naloxone