title: Intraamygdaloid microinjection of RFamide-related peptide-3 decreases food intake in rats.
abstract: Some members of the RFamide peptide family are associated with feeding in rodents. For example, neuropeptide FF and prolactin-releasing peptide cause anorexigenic, while 26RFa and QRFP result in orexigenic effects. I.c.v. microinjection of RFamide-related peptide-3 (RFRP-3) facilitates feeding. Feeding related effects of RFRP-3, however, have not been studied after direct brain microinjections in rats. The central part of amygdala (CeA) is essentially involved in the regulation of feeding and body weight. RFRP-3 positive nerve cells were detected in the rat hypothalamus and RFRP-3 immunoreactive fibers were identified in the CeA. RFRP analogs bind with relatively high affinity to the NPFF1 and NPFF2 receptors (NPFF-R). RFRP-3 has potent activity for NPFF-1 that is expressed in the CeA. To evaluate the role of RFRP-3 in feeding regulation rats were microinjected with different doses of RFRP-3 and their food intake were quantified over a 60 min period. Liquid food intake of male Wistar rats was measured after bilateral intraamygdalar administration of RFRP-3 (25, 50, 100 or 200 ng/side, RFRP-3 dissolved in 0.15M sterile NaCl/0.4 μl, respectively). The 50 ng and 100 ng doses of RFRP-3 microinjections resulted in significant decrease of food intake. Twenty-five and 200 ng had no effect. Food intake decreasing effect of RFRP-3 was eliminated by NPFF-R antagonist RF9 pretreatment. In open-field test effective doses of RFRP-3 did not modify spontaneous locomotor activity and general behavior of animals did not change. Our results are the first reporting that RFRP-3 injected to the CeA resulted in a decrease of liquid food consumption. This is a receptor-linked effect because it was eliminated by NPFF-R antagonist.
authors.affiliation: Institute of Physiology, Pécs University Medical School, Pécs, Hungary.
authors.forename: Anita
authors.initials: A
authors.lastname: Kovács
authors.affiliation: Institute of Physiology, Pécs University Medical School, Pécs, Hungary.
authors.forename: Kristóf
authors.initials: K
authors.lastname: László
authors.affiliation: Institute of Physiology, Pécs University Medical School, Pécs, Hungary.
authors.forename: Rita
authors.initials: R
authors.lastname: Gálosi
authors.affiliation: Institute of Physiology, Pécs University Medical School, Pécs, Hungary.
authors.forename: Tamás
authors.initials: T
authors.lastname: Ollmann
authors.affiliation: Institute of Physiology, Pécs University Medical School, Pécs, Hungary.
authors.forename: László
authors.initials: L
authors.lastname: Péczely
authors.affiliation: Institute of Physiology, Pécs University Medical School, Pécs, Hungary.
authors.forename: Olga
authors.initials: O
authors.lastname: Zagoracz
authors.affiliation: Institute of Physiology, Pécs University Medical School, Pécs, Hungary.
authors.forename: Noémi
authors.initials: N
authors.lastname: Bencze
authors.affiliation: Institute of Physiology, Pécs University Medical School, Pécs, Hungary; Molecular Neurophysiology Research Group, Pécs University, Szentágothai Research Center, Pécs, Hungary. Electronic address: Laszlo.Lenard@aok.pte.hu.
authors.forename: László
authors.initials: L
authors.lastname: Lénárd
mesh_terms: D000818:Animals; D066274:Central Amygdaloid Nucleus / Q000187:drug effects / Q000502:physiology*; D004435:Eating / Q000187:drug effects / Q000502:physiology*; D007028:Hypothalamic Hormones / Q000008:administration & dosage / Q000494:pharmacology / Q000502:physiology*; D008297:Male; D008845:Microinjections; D009043:Motor Activity / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar
chemical_list: D007028:Hypothalamic Hormones; C000588859:RFamide-related peptide-3, rat
keywords: Amygdala; Food intake; General activity; NPFF-R antagonist RF9; Neuropeptide RFRP-3