| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 6262000 | Brain Research Bulletin | 2012 | 7 Pages |
Several members of the RFamide peptide family are known to have role in the regulation of feeding. For example, neuropeptide FF and prolactin-releasing peptide cause anorexigenic, while 26RFa and QRFP result in orexigenic effects in rodents. I.c.v. microinjection of neuropeptide RFRP-1 significantly reduced food and water intake in chicks. However, feeding related effects of RFRP-1 have not been studied in mammals yet. The central part of amygdala (CeA) is essentially involved in the regulation of feeding and body weight. RFRP-1 positive nerve cells were detected in the rat hypothalamus and RFRP-1 immunoreactive fibers were identified in the CeA. RFRP analogs bind with relatively high affinity to the NPFF1 and NPFF2 receptors (NPFF-R). RFRP-1 has potent activity for NPFF1. Significant expression of NPFF1 was detected in the CeA. To evaluate the role of RFRP-1 in feeding regulation rats were microinjected with different doses of RFRP-1 and their food intake were quantified over a 60 min period. Liquid food intake of male Wistar rats was measured after bilateral intraamygdaloid administration of RFRP-1 (25, 50 or 100 ng/side, RFRP-1 dissolved in 0.15 M sterile NaCl/0.4 μl, respectively). The 50 ng dose of RFRP-1 microinjections resulted in significant decrease of food intake. The 25 and 100 ng had no effect. Action of 50 ng (37.8 pmol) RFRP-1 was eliminated by 20 ng (41.4 pmol) RF9 NPFF-R antagonist pretreatment. In open-field test 50 ng RFRP-1 did not modify spontaneous locomotor activity and general behavior of animals did not change. Our results are the first reporting that RFRP-1 injected to the CeA result in a decrease of liquid food consumption. This is a receptor-linked effect because it was eliminated by a NPFF-R selective antagonist.
⺠RFRP-1 belonging to the RFamide peptide family was microinjected to the amygdala. ⺠RFRP-1 in 50 ng dose decreases liquid food intake in rats. ⺠NPFF receptor antagonist RF9 pretreatment prevents RFRP-1 effect in the amygdala. ⺠These results are the first to show feeding related effects of RFRP-1 in mammals.
