title: Isolation, characterization, and distribution of a novel neuropeptide, Rana RFamide (R-RFa), in the brain of the European green frog Rana esculenta.
abstract: A novel neuropeptide of the RFamide peptide family was isolated in pure form from a frog (Rana esculenta) brain extract by using reversed-phase high performance liquid chromatography in combination with a radioimmunoassay for mammalian neuropeptide FF (NPFF). The primary structure of the peptide was established as Ser-Leu-Lys- Pro-Ala-Ala-Asn-Leu-Pro-Leu- Arg-Phe-NH(2). The sequence of this neuropeptide, designated Rana RFamide (R-RFa), exhibits substantial similarities with those of avian LPLRFamide, gonadotropin-inhibitory hormone, and human RFRP-1. The distribution of R-RFa was investigated in the frog central nervous system by using an antiserum directed against bovine NPFF. In the brain, immunoreactive cell bodies were primarily located in the hypothalamus, i.e., the anterior preoptic area, the suprachiasmatic nucleus, and the dorsal and ventral hypothalamic nuclei. The most abundant population of R-RFa-containing neurons was found in the periependymal region of the suprachiasmatic nucleus. R-RFa- containing fibers were widely distributed throughout the brain from the olfactory bulb to the brainstem, and were particularly abundant in the external layer of the median eminence. In the spinal cord, scattered immunoreactive neurons were found in the gray matter. R-RFa-positive processes were found in all regions of the spinal cord, but they were more abundant in the dorsal horn. This study provides the first characterization of a member of the RFamide peptide family in amphibians. The occurrence of this novel neuropeptide in the hypothalamus and median eminence and in the dorsal region of the spinal cord suggests that, in frog, R-RFa may exert neuroendocrine activities and/or may be involved in the transmission of nociceptive stimuli.
authors.affiliation: European Institute for Peptide Research (IFRMP 23), Laboratory of Cellular and Molecular Neuroendocrinology, INSERM U-413, UA CNRS, University of Rouen, 76821 Mont- Saint-Aignan, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Chartrel
authors.forename: Cynthia
authors.initials: C
authors.lastname: Dujardin
authors.forename: Jérôme
authors.initials: J
authors.lastname: Leprince
authors.forename: Laurence
authors.initials: L
authors.lastname: Desrues
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: Tonon
authors.forename: Eric
authors.initials: E
authors.lastname: Cellier
authors.forename: Pascal
authors.initials: P
authors.lastname: Cosette
authors.forename: Thierry
authors.initials: T
authors.lastname: Jouenne
authors.forename: Guy
authors.initials: G
authors.lastname: Simonnet
authors.forename: Hubert
authors.initials: H
authors.lastname: Vaudry
mesh_terms: D000595:Amino Acid Sequence / Q000502:physiology; D000818:Animals; D001369:Axons / Q000378:metabolism / Q000648:ultrastructure; D001921:Brain / Q000166:cytology / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D007031:Hypothalamus / Q000166:cytology / Q000378:metabolism; D007150:Immunohistochemistry; D008297:Male; D009434:Neural Pathways / Q000166:cytology / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D009479:Neuropeptides / Q000302:isolation & purification*; D011863:Radioimmunoassay; D011893:Rana esculenta / Q000033:anatomy & histology / Q000378:metabolism*; D013116:Spinal Cord / Q000166:cytology / Q000378:metabolism*
chemical_list: D009479:Neuropeptides; C416987:RFamide peptide